D&D 5E Looking for monsters to challenge a party of 6 level 17 characters

[dave2008]

Running out of MM options! On the upside the players aint that tactically brilliant.

At the moment I really need a non-boss not-smart single monster of large or huge size.

For 6 people at 17th level you would need a solo monster with a CR about lvl +10 and per the epic encounter guidelines you could need up to a CR 30 solo monster. So, here are your "official" options (from DnD Beyond):


30 Aspect of Bahamut Fizban's Treasury Of Dragons
30 Aspect of Tiamat Fizban's Treasury Of Dragons
27 Black Greatwyrm Fizban's Treasury Of Dragons
27 Blue Greatwyrm Fizban's Treasury Of Dragons
28 Brass Greatwyrm Fizban's Treasury Of Dragons
28 Bronze Greatwyrm Fizban's Treasury Of Dragons
28 Copper Greatwyrm Fizban's Treasury Of Dragons
28 Gold Greatwyrm Fizban's Treasury Of Dragons
27 Green Greatwyrm Fizban's Treasury Of Dragons
28 Rak Tulkhesh Eberron: Rising From The Last War
27 Red Greatwyrm Fizban's Treasury Of Dragons
28 Silver Greatwyrm Fizban's Treasury Of Dragons
28 Sul Khatesh Eberron: Rising From The Last War
30 Tarrasque Basic Rules
30 Tiamat Rise Of Tiamat
27 White Greatwyrm Fizban's Treasury Of Dragons

Not a wide range as the greatwyrms on actually only 2 stat blocks. Now, I have created some high CR monsters of my own. Here is partial list of the high CR monsters I have that might work for you:

CR 27:
Black Dragon, Wyrm (Legendary)
Black Dragon, Great Wyrm (Elite)
Empyrean (Legendary)
Hezrou Horde (Legendary)
Kord (Legendary)
Warforged Juggernaut (Elite)

CR 28:
Demogorgon (Elite)*
Green Dragon, Wyrm (Legendary)
Green Dragon, Great Wyrm (Elite)
Zakum (Legendary)

CR 29:
Blue Dragon, Wyrm (Legendary)
Blue Dragon, Great Wyrm (Elite)
Dragotha (Elite)
Genius Loci (Legendary)
Gigante (Elite)

CR 30:
Desert Leviathan (Elite)
Phaethon (Legendary)
Red Dragon, Wyrm (Legendary)
Red Dragon, Great Wyrm (Elite)
Tarrasque, Primordial (Elite)

CR 32:
Hecatoncheires (Elite)
Tiamat (Elite)

*Elite is the LevelUp version of "Mythic"

 

[dave2008]

Leviathan wouldn't fit through the door!

For this particular encounter I've decided to go with a slightly tweaked version of Polukranus, the legendary hydra from Theros, genericed to "Ancient Hydra".

My players are a pain "we want to play all the way to level 20!" grumble grumble

If that is your plan, I hope one of those tweaks is to make the hydra a mythic monster. As it stands it would not last very long vs 6 lvl 17 characters. You really need something with a CR about 8 higher than Polu.

If you have Theros I would look at Astra or Hythonia as better options.

 

[dave2008]

Yeah, done a bit of that (the boss is a legendary-ed Death Knight). There aren't many non-unique standard monsters even near the correct CR though (around 23). Not every fight can be against an archdevil or demon prince!

Actually, you are looking at a CR form 27-30 for a group that size and lvl.

 

[Paul Farquhar]

An idea for you: when they cut one of the heads off it becomes an independent floating hydra head. Which needs killing.

I just gave it Legendary Action: Grow another Head

 

[Baldurs_Underdark]

If a Giant Ape is not a challenge to your party anymore, just give them 50 Giant Apes to fight, in a forest environment.

Top tip, have the Apes act in little groups of 5, so you can roll their attacks simultaneously (roll 5d20, result: hit miss miss hit miss), then roll all damage at once.

 

[dave2008]

Ok, I did a little more research and you "should" be looking at a mythic monster of CR 23+ or a legendary monster of CR 27+. Beyond the list I gave you before, here are some additional monsters that fit that category (from DnD Beyond):

24 Ancient Dragon Turtle Fizban's Treasury Of Dragons
26 Tromokratis Mythic Odysseys Of Theros
26 Amethyst Greatwyrm Fizban's Treasury Of Dragons
26 Ancient Amethyst Dragon Fizban's Treasury Of Dragons
26 Crystal Greatwyrm Fizban's Treasury Of Dragons
26 Emerald Greatwyrm Fizban's Treasury Of Dragons
26 Sapphire Greatwyrm Fizban's Treasury Of Dragons
26 Topaz Greatwyrm Fizban's Treasury Of Dragons

And a few more of my monsters:

CR 24:
Rajara (Mythic) by Just Passing Through

CR 25:
Acererak (Mythic)

CR 26:
Seraphim (Elite)
White Dragon, Great Wyrm (Elite)

 

[Paul Farquhar]

For 6 people at 17th level you would need a solo monster with a CR about lvl +10 and per the epic encounter guidelines you could need up to a CR 30 solo monster. So, here are your "official" options (from DnD Beyond):


30 Aspect of Bahamut Fizban's Treasury Of Dragons
30 Aspect of Tiamat Fizban's Treasury Of Dragons
27 Black Greatwyrm Fizban's Treasury Of Dragons
27 Blue Greatwyrm Fizban's Treasury Of Dragons
28 Brass Greatwyrm Fizban's Treasury Of Dragons
28 Bronze Greatwyrm Fizban's Treasury Of Dragons
28 Copper Greatwyrm Fizban's Treasury Of Dragons
28 Gold Greatwyrm Fizban's Treasury Of Dragons
27 Green Greatwyrm Fizban's Treasury Of Dragons
28 Rak Tulkhesh Eberron: Rising From The Last War
27 Red Greatwyrm Fizban's Treasury Of Dragons
28 Silver Greatwyrm Fizban's Treasury Of Dragons
28 Sul Khatesh Eberron: Rising From The Last War
30 Tarrasque Basic Rules
30 Tiamat Rise Of Tiamat
27 White Greatwyrm Fizban's Treasury Of Dragons

Not a wide range as the greatwyrms on actually only 2 stat blocks. Now, I have created some high CR monsters of my own. Here is partial list of the high CR monsters I have that might work for you:

CR 27:
Black Dragon, Wyrm (Legendary)
Black Dragon, Great Wyrm (Elite)
Empyrean (Legendary)
Hezrou Horde (Legendary)
Kord (Legendary)
Warforged Juggernaut (Elite)

CR 28:
Demogorgon (Elite)*
Green Dragon, Wyrm (Legendary)
Green Dragon, Great Wyrm (Elite)
Zakum (Legendary)

CR 29:
Blue Dragon, Wyrm (Legendary)
Blue Dragon, Great Wyrm (Elite)
Dragotha (Elite)
Genius Loci (Legendary)
Gigante (Elite)

CR 30:
Desert Leviathan (Elite)
Phaethon (Legendary)
Red Dragon, Wyrm (Legendary)
Red Dragon, Great Wyrm (Elite)
Tarrasque, Primordial (Elite)

CR 32:
Hecatoncheires (Elite)
Tiamat (Elite)

*Elite is the LevelUp version of "Mythic"

The trouble with most of those is they are designed for boss fights. It's the filler which is more difficult.

If you have Theros I would look at Astra or Hythonia as better options

Both of those (reskinned) are scheduled for later. And Tromokratis. MooT is a good source for this.

Actually, you are looking at a CR form 27-30 for a group that size and lvl.

As I mentioned, by players are not very tactically adept. I've nearly accidently TPKed them on a number of occasions. Adjust CR down based on player skill.

 

[Paul Farquhar]

If a Giant Ape is not a challenge to your party anymore, just give them 50 Giant Apes to fight, in a forest environment.

This just makes for a very dull fight. Besides, 50 giant apes would have trouble fitting in a 30 ft. square room.

 

[Helldritch]

This works quite well for me.
Single encounter big bad guys
Add 1 feat/ASI per 4 CR (save the first four)
Add 1 legendary action per PC above 4.
Multiply HP by 1 +0.25 per PC above 4.
Add 1.5 AC (round up) per PC above 4.

Here is a modified lich my players defeated at 17th level in a previous campaing.


AC: 17 (natural armor + dex) Now 23 (+1.5 AC x 2 for players number, Staff of power and +1 ring. It could go up to 25 for one attack because of the shield guardian and I am not counting shield. Since shield was an at will power, it became and AC 28 and 30 for one attack)
HP: 135 (18d8 + 54) Now 238 for a 1.5 multiplyer for number of players and tough feat (+36hp).
Spd: 30' (unchanged)
Stats: Unchanged (decided to use feats instead...)
Added: Warcaster, Elemental Adept Fire (that one was a surprise for my players), Tough.
Mage feature added: Shield and Mirror image at will (I counted that one as a feat)
Spell list was changed to reflect the added mage feature and feats.
Cantrip: Removed prestigiditation and added Fire Bolt. Rose number of cantrip to four and added Green Flame blade
Level 1: Removed shield and added disguise self (Lich used it to appear human as she did in her life.)
Level 2: Removed Mirror image and added Misty step instead.

Legendary action Rose to 5 (again 6 players)

Lich was also using Staff Of Power And a Shield Guardian.
Add to it the "Mythic" treatment and you got one hell of big bad boy.

 

[dave2008]

The trouble with most of those is they are designed for boss fights. It's the filler which is more difficult.

Both of those (reskinned) are scheduled for later.

As I mentioned, by players are not very tactically adept. I've nearly accidently TPKed them on a number of occasions. Adjust CR down based on player skill.

Ok, I missed that this was a "filler" battle and not a boss-type battle. Seems like you've got a plan, so good luck!