Special Conversion Thread: Lycanthropes and their ilk

[Cleon]

Weapon Focus (bite) and Stealthy work for me.

I like those org lines.

Updating Greater Wererat Working Draft.

Tactics: Greater wererats prefer to fight in hybrid form, biting opportunistically.

Let's see...

How's this?

Greater wererats use their animal or human forms to spy on enemies and set up ambushes, but favor their hybrid form for fighting. Given time, they use summon rodents to call rat allies to send into combat. Most greater wererats treat their rodent and ratwere underlings as disposable chattels, and are unlikely to risk their own skin to protect them.

I have to admit I don't have much for these. They're pretty simple.

Yes, we don't need much for the background text.

 

[freyar]

That's a bit better for tactics!


Background: Greater wererats are close cousins of the common wererat and the ratwere but with greater strength and power. While they shun the common wererat, greater wererats often rise to leadership among colonies of ratweres, whom they look down upon as little better than slaves.

???

 

[Cleon]

That's a bit better for tactics!

Updating Greater Wererat Working Draft.

Background: Greater wererats are close cousins of the common wererat and the ratwere but with greater strength and power. While they shun the common wererat, greater wererats often rise to leadership among colonies of ratweres, whom they look down upon as little better than slaves.

???

Hmm, I think it makes sense to mention their strain of lycanthropy (the ratwere one) only transforms dire rats and humans and is lethal to other creatures.

Let me think about it for a bit...

 

[freyar]

Background: Greater wererats are close cousins of the common wererat and the ratwere but with greater strength and power. While they shun the common wererat, greater wererats often rise to leadership among colonies of ratweres, whom they look down upon as little better than slaves. They are infected with a potent form of lycanthropy, the ratwere plague, which kills most creatures and transforms humans and dire rats into lycanthropes.

 

[Cleon]

Background: Greater wererats are close cousins of the common wererat and the ratwere but with greater strength and power. While they shun the common wererat, greater wererats often rise to leadership among colonies of ratweres, whom they look down upon as little better than slaves. They are infected with a potent form of lycanthropy, the ratwere plague, which kills most creatures and transforms humans and dire rats into lycanthropes.

I think we can do without the "but with greater strength and power" in the first sentence.

The bit about the colonies could do with a touch of elaboration, and I think it belongs at the end instead of the sentence about the ratwere plague.

How's this?

Greater wererats are close kin to common wererats and ratweres. They are infected with a potent form of lycanthropy, the ratwere plague, which transforms humans and dire rats into lycanthropes and is fatal to most other creatures. While they shun the common wererat, greater wererats often rule colonies of ratweres, rats and dire rats. Greater wererats casually devour their rodent minions whenever food runs short, and even a gifted ratwere is looked down upon as little better than a slave.

 

[freyar]

That looks good to me.

I think they're all done after an update!

 

[Cleon]

That looks good to me.

I think they're all done after an update!

Updating Greater Wererat Working Draft.

I modified the standard "The were*** presented here" sentence to remove the reference to "natural lycanthrope".

It was also missing an accreditation, so I used Dungeon #88, since The Wererats of Relfen adventure in that issue was the earliest source I could find that used the name "Greater Wererats" for the human-type BECMI wererat.

 

[freyar]

Looks good to me! I guess we should move to the next one.

 

[Cleon]

Looks good to me! I guess we should move to the next one.

The next one is the Wererat Lord, which is the last creature in the Skinchangers batch - so once we convert it we can finally add an update to the CC!

 

[Cleon]

Wererat Lord Original Stats

Wererat Lord
CLIMATE/TERRAIN: Any
FREQUENCY: Very rare
ORGANIZATION: Pack
ACTIVITY CYCLE: Nocturnal
DIET: Scavenger
INTELLIGENCE: High to genius (13–18)
TREASURE: C, I
ALIGNMENT: CE
NO. APPEARING: 4-24
ARMOR CLASS: 6 or better
MOVEMENT: 12
HIT DICE: 3+1 or better
THAC0: Varies
NO. OF ATTACKS: 1
DAMAGE/ATTACK: By weapon
SPECIAL ATTACKS: Surprise
SPECIAL DEFENSES: Hit only by silver or +1 or better weapons
MAGIC RESISTANCE: Nil
SIZE: S-M (3’–6’)
MORALE: Elite (13–14)
XP VALUE: varies

Wererat lords are the aristocracy of their genotype and as such are capable of much more than ordinary lycanthropes. They generally live longer than others of their genotype who regard them as something near divine. Some wererat lords live as long as 200 years. Other lycanthrope lords are certain to exist, but their discovery has yet to be recorded.

In appearance, the wererat lord is pretty indistinguishable from ordinary wererats.

Combat: Wererats lords differ from normal wererats in one major respect: they have no upper limit to class or Hit Dice level (except that normally dictated by rare and/or class). Most wererat lords are thieves (75%) and on occasion mages (mage 10%. Thief/mage 5%). Their Hit Dice and class level advance at the same rate, thus a 16th-level human wererat lord thief would attack as a 16th-level rogue in human form and as a 16 HD monster in man-rat form.

As with their mundane cousins, wererat lords prefer cold steel in combat to tooth and claw. Even better, they prefer to use missile weapons from a safe place, or else set traps and ambushes.

Wererat lords infect their victims with the lycanthropic virus in the same way that ordinary wererats do. However infected victims of the lords are treated in the same way as ordinary lycanthropes; they cannot advance in level as the lords do. Wererat lords are born, not made, and must be sired by two wererat lords. The chance of being infected with the lycanthropic virus is much higher than normal, being 2% chance per hp damage inflicted by the lord.

Wererat lords are usually lead by a clan leader who as head of his clan is heir to several abilities. A clan leader can summon a pack of giant rats and can control all of the common wererats infected by him. This control is an ability to trigger the infected wererats transformation into their manrat form, but they must be able to see him to achieve this.

Habitat/Society: Wererats lords live in closely knit packs trusting no one but their own immediate clan. Clan family members may conspire against each other, but they are always united against any outside enemies.

Wererat lords are attracted to cities where they can thieve and murder in comfort. They generally try to surround themselves with devoted followers such as ordinary wererats or infected victims. These followers are rarely selected for their intelligence, as they are merely expendable pawns to do the lords’ dirty work. Once a city has yielded up its treasures, or becomes too hot to hold them, the wererat lords move on to the next town.

Ecology: Wererat lords are parasites on the parasites. Not only do they feed off humankind and steal their riches, they use their own common kind to do so. Like cuckoos, they will infest the lair of a clan of wererats or a thieves guild to provide themselves with a comfortable nest to live in. While initially beneficial, this usually spells doom for the hosts in question; the lords are only interested in themselves and think nothing of sacrificing their followers to protect their own miserable hides.

 

[Cleon]

Wererat Lord

So, basically the AD&D Wererat Lord is a natural lycanthrope Wererat with better mental abilities (Int 13-18 instead of 11-12), unlimited class advancement and a longer lifespan (up to 200 years), whose "clan leaders" are able to summon packs of giant rats and control all wererats infected by them (and their form of Lycanthropy is more virulent, with double the standard infection chance).

They are also Chaotic Evil and prey off Lawful Evil standard Wererats "like cuckoos".

For the sake of this conversion, I suggest we make all Wererat Lords have the summoning power and the ability to dominate wererats - they are called "Lords" after all.

I believe I already mentioned I'd give them Damage Reduction in all their forms, since (a) that's a common feature of other "Lycanthrope Lord" monsters and (b) it doesn't explicitly say their "hit only by silver or magic" only applies in animal or hybrid form.

I also fancied giving them the ability to summon wererats like a high-level greater wererat in PC4 Night Howlers can. We could restrict this ability to a "clan leader", since a PC4 had to advance five levels above "Normal Monster" to gain that ability.

For the stats, I suggest taking a Greater Wererat and adding a few ability increases - +2 Int and +2 Cha seems a minimum - then modifying the Greater Wererats special abilities.

Since they're "capable of much more than ordinary wererats" I suggest most of them are elite NPCs with levels in adventuring classes. I'd use a 1st level rogue for the "ordinary wererat lord" and a rogue/wizard for the "clan leader".

Should be pretty straightforward to write up.

 

[freyar]

So, basically the AD&D Wererat Lord is a natural lycanthrope Wererat with better mental abilities (Int 13-18 instead of 11-12), unlimited class advancement and a longer lifespan (up to 200 years), whose "clan leaders" are able to summon packs of giant rats and control all wererats infected by them (and their form of Lycanthropy is more virulent, with double the standard infection chance).

They are also Chaotic Evil and prey off Lawful Evil standard Wererats "like cuckoos".

For the sake of this conversion, I suggest we make all Wererat Lords have the summoning power and the ability to dominate wererats - they are called "Lords" after all.

Agreed. I think I'd also bump the racial HD, make them dire lycanthropes (like the CC template), or something.

I believe I already mentioned I'd give them Damage Reduction in all their forms, since (a) that's a common feature of other "Lycanthrope Lord" monsters and (b) it doesn't explicitly say their "hit only by silver or magic" only applies in animal or hybrid form.

Which lycanthrope lords are you talking about? The SRD werewolf lord doesn't have DR in all forms, though it's just a normal lycanthrope. I'm not saying I disagree, but I don't quite follow the logic.

I also fancied giving them the ability to summon wererats like a high-level greater wererat in PC4 Night Howlers can. We could restrict this ability to a "clan leader", since a PC4 had to advance five levels above "Normal Monster" to gain that ability.

For the stats, I suggest taking a Greater Wererat and adding a few ability increases - +2 Int and +2 Cha seems a minimum - then modifying the Greater Wererats special abilities.

Since they're "capable of much more than ordinary wererats" I suggest most of them are elite NPCs with levels in adventuring classes. I'd use a 1st level rogue for the "ordinary wererat lord" and a rogue/wizard for the "clan leader".

Should be pretty straightforward to write up.

Yes, I'll agree with all that.

 

[Cleon]

Agreed. I think I'd also bump the racial HD, make them dire lycanthropes (like the CC template), or something.

I was thinking 3 Hit Dice like our Greater Wererat would be enough. How many do you want?

Which lycanthrope lords are you talking about? The SRD werewolf lord doesn't have DR in all forms, though it's just a normal lycanthrope. I'm not saying I disagree, but I don't quite follow the logic.

I was thinking of things like the Jackal Lord, which has DR in all its forms, although that isn't a true lycanthrope.

In the case of the Ratlord, I was motivated more by the idea that they're the "next stage up" from a Greater Wererat, since they have the ability to summon & control regular Wererats, which is also possessed by high-level Greater Wererats in the BECMI Night Howlers source. Furthermore, those wererats have a special ability to retain their damage reduction in human form, which we've already given to our Greater Wererat conversion.

Yes, I'll agree with all that.

OK, I'll start a working draft.

Are you OK with the propose racial boni of +2 Int and +2 Cha in addition to the standard lycanthrope's +2 Wis?

 

[Cleon]

Just noticed that the Greater Wererat Working Draft had a feat mismatch. Namely it had three feats plus four bonus feats while only having enough Hit Dice for two regular feats.

I've fixed the problem by making Stealthy another bonus feat.

Indeed, I think we'd already agreed to do that, since I originally gave them Stealthy because that's something standard rats have.

EDIT: Furthermore, the animal and hybrid forms have Strength 16 which ought to be 17. I've corrected it.

 

[Cleon]

Wererat Lord Working Draft

Lycanthrope, Wererat Lord

Wererat Lord, Human Form
Medium Humanoid (Human, Shapechanger)
Hit Dice: 1d6+1 plus 3d10+12 (33 hp)
Initiative: +6
Speed: 30 ft. (6 squares)
Armor Class: 17 (+2 Dex, +2 natural, +2 leather, +1 buckler) touch 12, flat-footed 12
Base Attack/Grapple: +3/+5
Attack: Rapier +5 melee (1d6+2/18–20) or heavy crossbow +5 ranged (1d10/19–20)
Full Attack: Rapier +5 melee (1d6+2/18–20) or heavy crossbow +5 ranged (1d10/19–20)
Space/Reach: 5 ft./5 ft.
Special Attacks: Command cursed wererat, sneak attack +1d6, summon ratkin
Special Qualities: Alternate form, damage reduction 5/silver, low-light vision, rodent empathy, scent, speak with rats, trapfinding
Saves: Fort +4, Ref +7, Will +6
Abilities: Str 14, Dex 15, Con 13, Int 14, Wis 12, Cha 10
Skills: Bluff +4* (+8 vs ratkin), Climb +10, Disable Device +6, Escape Artist +6, Hide +13, Intimidate +4* (+8 vs ratkin), Listen +10, Move Silently +13, Search +6, Sleight of Hand +6, Spot +10, Swim +10, Tumble +6
Feats: Alertness (B), Improved Initiative, Iron Will (B), Multiattack (B), Point Blank Shot, Stealthy (B), Weapon Finesse (B)
Environment: Urban and underground
Organization: Solitary, pack (2-8), infestation (2-8 plus 4-16 wererats), troupe (2-8 plus 11-20 dire rats or rat swarms) or clan (2-16 plus one 5th-8th clan level leader and 6-24 wererats and 2-40 dire rats or rat swarms)
Challenge Rating: 4
Treasure: Standard
Alignment: Always chaotic evil
Advancement: By character class
Level Adjustment: +3

Wererat Lord, Dire Rat Form
Medium Humanoid (Human, Shapechanger)
Hit Dice: 1d6+1 plus 3d10+12 (33 hp)
Initiative: +9
Speed: 40 ft. (8 squares), climb 20 ft., swim 20 ft.
Armor Class: 18 (+5 Dex, +3 natural), touch 15, flat-footed 13
Base Attack/Grapple: +3/+7
Attack: Bite +8 melee (1d6+6 plus curse of the ratlord)
Full Attack: Bite +8 melee (1d6+6 plus curse of the ratlord)
Space/Reach: 5 ft./5 ft.
Special Attacks: Command cursed wererat, curse of the ratlord, sneak attack +1d6, summon ratkin
Special Qualities: Alternate form, damage reduction 10/silver, low-light vision, rodent empathy, scent, speak with rats, trapfinding
Saves: Fort +7, Ref +10, Will +6
Abilities: Str 18, Dex 21, Con 19, Int 14, Wis 12, Cha 10
Skills: Bluff +4* (+8 vs ratkin), Climb +12, Disable Device +9, Escape Artist +9, Hide +16, Intimidate +4* (+8 vs ratkin), Listen +10, Move Silently +16, Search +6, Sleight of Hand +9, Spot +10, Swim +12, Tumble +9
Feats: Alertness (B), Improved Initiative, Iron Will (B), Multiattack (B), Point Blank Shot, Stealthy (B), Weapon Finesse (B)
Environment: Urban and underground
Organization: Solitary, pack (2-8), infestation (2-8 plus 4-16 wererats), troupe (2-8 plus 11-20 dire rats or rat swarms) or clan (2-16 plus one 5th-8th clan level leader and 6-24 wererats and 2-40 dire rats or rat swarms)
Challenge Rating: 4
Treasure: Standard
Alignment: Always chaotic evil
Advancement: By character class
Level Adjustment: +3

Wererat Lord, Hybrid Form
Medium Humanoid (Human, Shapechanger)
Hit Dice: 1d6+1 plus 3d10+12 (33 hp)
Initiative: +9
Speed: 40 ft. (8 squares), climb 20 ft., swim 20 ft.
Armor Class: 18 (+5 Dex, +3 natural), touch 15, flat-footed 13
Base Attack/Grapple: +3/+7
Attack: Rapier +8 melee (1d6+4/18–20) or bite +8 melee (1d6+6 plus curse of the ratlord) or heavy crossbow +8 ranged (1d10/19–20)
Full Attack: Rapier +8 melee (1d6+4/18–20) and bite +6 melee (1d6+2 plus curse of the ratlord); or heavy crossbow +8 ranged (1d10/19–20)
Space/Reach: 5 ft./5 ft.
Special Attacks: Command cursed wererat, curse of the ratlord, sneak attack +1d6, summon ratkin
Special Qualities: Alternate form, damage reduction 10/magic or silver, low-light vision, rodent empathy, scent, speak with rats, trapfinding
Saves: Fort +7, Ref +10, Will +6
Abilities: Str 18, Dex 21, Con 19, Int 14, Wis 12, Cha 10
Skills: Bluff +4* (+8 vs ratkin), Climb +12, Disable Device +9, Escape Artist +9, Hide +16, Intimidate +4* (+8 vs ratkin), Listen +10, Move Silently +16, Search +6, Sleight of Hand +9, Spot +10, Swim +12, Tumble +9
Feats: Alertness (B), Improved Initiative, Iron Will (B), Multiattack (B), Point Blank Shot, Stealthy (B), Weapon Finesse (B)
Environment: Urban and underground
Organization: Solitary, pack (2-8), infestation (2-8 plus 4-16 wererats), troupe (2-8 plus 11-20 dire rats or rat swarms) or clan (2-16 plus one 5th-8th clan level leader and 6-24 wererats and 2-40 dire rats or rat swarms)
Challenge Rating: 4
Treasure: Standard
Alignment: Always chaotic evil
Advancement: By character class
Level Adjustment: +3

Wererat lords are a powerful form of natural lycanthrope who regard themselves as the aristocratic rulers of wererat kind. Many ordinary wererats worship wererat lords with nearly religious devotion, but most wererat lords view their lesser kin as nothing but expendable pawns.

Wererat lords live by themselves or in small family groups surrounded by obedient (and usually dim-witted) servants, usually common wererats created by the wererat lord's infectious bite. They prefer to live in large settlements such as cities, where they can murder, devour and steal from humanoids while hiding in their midst. Their normal strategy is to take over a small guild or noble house by infecting all its members with lycanthropy, and then live in luxury off the labour and wealth of their infected slaves. Thieves guilds are a favorite target. They quickly move on to the next town once they've drained the neighbourhood of treasure or if the locals become too suspicious.

All known wererat lords have been human, but extraordinarily long lived ones - a wererat lord's lifespan is fully twice that of a normal human. Wererat lords are very rare, probably because they only produce more of their kind when they mate with another wererat lord.

COMBAT
Wererat lords are cowardly creatures who would rather use their summon ratkin power and wererat minions to do their fighting for them. They prefer ranged attacks, ambushes, and traps over melee combat. Wererat lords prefer to fight with manufactured rather than natural weapons, using their class abilities extensively.

A wererat lord will quickly abandon its followers to save its own skin, but may be willing to take a few risks to save another member of its tight-knit family.

Alternate Form (Su): A wererat lord can assume a bipedal hybrid form or the form of a man-sized dire rat.

Command Cursed Wererat (Su): A wererat lord can command the obedience of any wererat they create with their curse of the ratlord ability. This functions like a command spell (no save).

At 8 HD, a wererat lord can command cursed wererats to "transform", which forces them to involuntarily transform into hybrid form.

Curse of the Ratlord (Su): Any humanoid or giant hit by the bite attack of a wererat lord in animal or hybrid form must succeed on a DC 15 Fortitude save or contract lycanthropy. The victims of this curse are in thrall to the wererat lord who created them and can be affected by the ratlord's command cursed wererat ability (see above). They are otherwise identical to a standard afflicted wererat.

Rodent Empathy: A wererat lord has a +4 racial bonus on Charisma-based checks against any animal or magical beast of the rodent family, including rats, dire rats and ratweres.

Speak With Rats (Su): A wererat lord can communicate with rats and dire rats as if it had a permanent speak with animals spell. It can also use this ability to speak with ratweres and other wererats using this ability, which sounds like rodent squeaks and chirps.

Summon Ratkin (Su): Once per day, as a standard action, a wererat lord can call forth 1d2 rat swarms or a pack of 2d6 dire rats. These creatures arrive in 2d6 rounds and serve the wererat for up to 1 hour.

A wererat lord's summoning ability increases as it gains additional hit dice. It can summon larger numbers of rodents, and at 8 Hit Dice it gains the ability to summon wererats. See the Wererat Lord Summoning Table for details.

A wererat lord can only use summon ratkin on wererats it personally created with its curse of the ratlord ability. If no such wererats exist, the wererat lord can only summon normal or dire rats.

Wererat Lord Summoning Table

Hit Dice	Cursed Wererats	Rat Swarms	Dire Rats
4-5	—	1d2	2d6
6-7	—	1d4	3d6
8-9	1d6+1	1d6+1	4d8
10-11	2d6	2d6	5d10
12+	3d6	3d6	8d10

Skills: Wererat lords have a +4 racial bonus on Hide and Move Silently checks and a +8 racial bonus on Climb and Swim checks. Wererat lords can use their Dexterity modifier or their Strength modifier for Climb and Swim checks, whichever is better.

In rat or hybrid-form, a wererat lord gains a +8 racial bonus on Balance checks and can always choose to take 10 on Climb and Swim checks, even if rushed or threatened. It can use the run action while swimming, provided it swims in a straight line.

Feats: Wererat lords gain Alertness, Iron Will, Multiattack, Stealthy and Weapon Finesse as bonus feats.

The wererat lord presented here is based on a 1st-level human rogue, using the following base ability scores: Str 14, Dex 15, Con 13, Int 12, Wis 10, Cha 8.

Wererat lord have racial ability bonuses of Intelligence +2, Wisdom +2 and Charisma +2.

Originally appeared in Dungeon #62 (1996).

Skill Breakdown
Human Rogue Skills (44 SPs): 11 skills @4?
Bluff 4, Disable Device 4, Escape Artist 4, Hide 4, Intimidate 4, Listen 4, Move Silently 4, Search 4, Sleight of Hand 4, Spot 4, Tumble 4
Ratwere Skills (12 SPs):
Hide 3, Listen 3, Move Silently 3, Spot 3
Skill Ranks (56 SPs): Bluff 4, Disable Device 4, Escape Artist 4, Hide 7, Intimidate 4, Listen 7, Move Silently 7, Search 4, Sleight of Hand 4, Spot 7, Tumble 4

 

[freyar]

Well, this looks really great! I like DR 5 for the human form and DR 10 for the others, too.

Only question: should we tie in with the ratweres and greater wererats in Summon Ratkin? And for Summon Ratkin, X=Y=2, Z=10?

 

[Cleon]

Well, this looks really great! I like DR 5 for the human form and DR 10 for the others, too.

Good! I'll update the Wererat Lord Working Draft to unred the DR 5.

Only question: should we tie in with the ratweres and greater wererats in Summon Ratkin?

I'd wondered about that, but the original could only summon giant rats and common wererats - and that was only for the clan leader: "A clan leader can summon a pack of giant rats and can control all of the common wererats infected by him".

I'd also wondered about making the ability grow stronger at higher levels, like the BECMI wererat character rules in PC4 - Night Howlers. They could summon lesser wererats (e.g. Ratweres) at higher levels, and could summon increasingly larger numbers of creatures.

Although, come to think of it, that PC4 wererat is the "greater wererat" we converted, so we should give that ability to it.

Anyhow, I'm OK adding the Ratwere to the summoning list, preferably for a higher level Lord, and would fancy adding it to the Greater Wererat for higher level examples.

And for Summon Ratkin, X=Y=2, Z=10?

I'd like there to be some random element, and would prefer the number to get larger (and/or the summoned creatures more powerful) with higher levels.

 

[freyar]

Hmm, well, I'd propose X=Y=1d4, Z=2d8, but I don't know how I'd want to increase things by HD. Did you have something in mind?

 

[Cleon]

Hmm, well, I'd propose X=Y=1d4, Z=2d8, but I don't know how I'd want to increase things by HD. Did you have something in mind?

I didn't have anything specific in mind.

Let's see.

The BECMI Night Howlers version of the summoning went:

NM-level - 1d2 giant rats (or 10d2 normal rats)
2nd-level - 1d4 giant rats (10d4 normal rats)
4th-level - 1d6 (or 10d6)
5th-level - can summon other wererats as well as giant rats (DM's decision as to numbers)
6th level - 1d8 (or 10d8)
8th level - 1d10 (or 10d10)
Every 4 levels thereafter, add 1d10 (or 10d10)

NM is 'normal monster', or a wererat without any additional levels.

For our 3rd edition update...

A wererat CR 2 and a rat swarm is also CR 2, so it makes sense to have them match in numbers.

A dire rat is CR 1/3, so three are CR 1 and six are CR 2.

Hmm, the 1d4 wererats you suggest is an EL 3 or 4 encounter, which seems a bit high for a CR 4 monster's summoning ability.

I'd prefer 1d2 as the starting summons, since (a) that's an EL 2 or 3 encounter and (b) that's also the "starting summons" of the Night Howler summons. 1d2 average at 1.5, so is roughly equal to nine dire rats is six dire rats is CR 2. 9 is the average of 2d8, the number you suggested. I'm a bit concerned that number will be a bit unwieldy, so I'd prefer a somewhat smaller range like 2d6.

From then, I suggest a progression of:

At 2nd level, it can summon 1d4 rat swarms or wererats or 2d10 dire rats.
At 4th level, it can summon 2d4 rat swarms or wererats or 4d10 dire rats.
For every 2 additional levels, it can summon an extra 2d4 rat swarms or wererats or 4d10 dire rats.

It might be easiest to express that in a little table, e.g.:

Wererat Lord Summoning Table

Hit Dice	Wererats	Rat Swarms	Dire Rats
4-5 (up to 1st level)	1d2	1d2	2d6
6-7 (2nd-3rd level)	1d4	1d4	2d10
8-9 (4th-5th level)	2d4	2d4	4d10
Every 2 additional HD	+2d4	+2d4	+4d10

Actually, once it reaches the higher levels, all those extra dire rats won't be much use, so I'm tempted to cap it at, say, 12 dice:

Wererat Lord Summoning Table

Hit Dice	Wererats	Rat Swarms	Dire Rats
4-5 (up to 1st level)	1d2	1d2	2d6
6-7 (2nd-3rd level)	1d4	1d4	2d10
8-9 (4th-5th level)	2d4	2d4	4d10
10-11 (6th-7th level)	4d4	4d4	8d10
12+ (8th+ level)	6d4	6d4	12d10

What thinks thee?

 

[freyar]

Seems fine to me. Did we want to slot in "or X ratweres" at some point? An equivalent EL would be something close to 1d6 at level 8-9, then 2d6 and 3d6 subsequently.