Hey Dingo!
If it's for a Night Hag, I'd prefer to make a race-specific PrC, since most of her HD are in her race (not in a class). Giving spellcasting advancement isn't going to help her much (compared to advancing a 9+ level spellcaster).
She's got 8 HD and she's CR 9. She's got some nice spell-like abilities, and some nice immunities, and a few very flavorful special abilities. First vital improvement: drop Combat Casting and Alertness and instead take Power Attack & some other useful Feat. (Great ones are Ride-By Attack and Spirited Charge.)
One other thing: Night Hags travel a lot. Consider allowing them to take the last 5 levels of Horizon Walker (the planar stuff) without taking the first 5 levels.
Anyway, here's my first brush at what a PrC for a sneaky Night Hag might look like. (Remember that Night Hags get +1 CR per two HD, so I don't want to simply replicate what Outsider HD can provide -- +1 BAB, 8 Skill Points, all good saves. You should balance your particular Night Hag with a mix of extra Outsider HD and levels in a PrC. Also, four levels of Fighter and then ten levels of Blackguard are already great for a combat-oriented Night Hag, so I'm not going in that direction, either.)
Hag Traveler
HD: d8
BAB: 3/4 (as Rogue)
Good Save: Will / Bad Saves: Fortitude, Reflex
Skill Points: 4 + Int bonus
Class Skills: Balance (Dex), Bluff (Cha), Climb (Str), Concentration (Con), Diplomacy (Cha), Disguise (Cha), Hide (Dex), Intimidate (Cha), Jump (Str), Knowledge (any) (Int), Listen (Wis), Move Silently (Dex), Ride (Dex), Sense Motive (Wis), Spellcraft (Int), Spot (Wis), Survival (Wis), Swim (Str) and Tumble (Dex).
Code:
[u]
Level BAB F/R/W Special Abilities [/u]
1 +0 +0/0/2 Favored Plane, [i] Undetectable Alignment [/i]
2 +1 +0/0/3 Sneak Attack +1d6, Subtle Transformation
3 +2 +1/1/3 Planar Adaptation
4 +3 +1/1/4 Sneak Attack +1d6, Planar Power
Special Abilities :
- Favored Plane (Sp/Su): The Night Hag chooses one plane from which she draws power. She gains the ability to Plane Shift to her favored plane 1/day. In addition, when on her favored plane, she gains a +4 Enhancement bonus to Str, Dex and Con. (Specific planes that a Night Hag may choose: Limbo, Pandemonium, the Abyss, Carceri, Hades, Gehenna, the Nine Hells, Acheron, the Ethereal, the Plane of Shadow, or any one Elemental).
- Undetectable Alignment (Sp): At will.
- Subtle Transformation (Su): The Night Hag's true form becomes harder to discover. When she is polymorphed, she gains a Will save against any effect that might reveal her to be transformed, including detect magic and true seeing .
- Planar Adaptation (Su): The Night Hag is treated as though she were a native to whatever plane she currently occupies. An Abyssal ocean of acid would not harm her, nor would the normal fires of the Elemental Plane of Fire. She gains a Will save against any effect that specifically targets non-natives, such as bolt of glory and the banishment portion of holy word .
- Planar Power : The Night Hag can draw great power from her chosen plane. She may now plane shift to her Favored Plane at will, and additionally gains one of the following benefits (as appropriate by plane):
- Limbo Tango (Sp): Dimension door at will.
- Pandemonic Shield (Sp): Wind wall and silence at will.
- Abyssal Madness (Su): The Night Hag's bite additionally deals one point of Wisdom damage.
- Carceri's Venom (Su): The Night Hag is shielded by a psychic poison effect of her choice at all times (see BoVD for details on psychic poison ).
- Malady of Hades (Ex): The Night Hag's bite threatens to inflict a second disease, determined randomly or chosen by the DM, in addition to Demon Fever.
- Gehennal Vision (Su): The Night Hag can see through smoke, natural or supernatural, as though it were clean air. This gives her a great advantage when fighting mounted on a Nightmare.
- Hellsight (Su): The Night Hag can see through darkness, natural or supernatural, and can constantly see invisibility as the spell.
- Warrior of Acheron (Ex): The Night Hag gains two claw attacks (secondary natural attacks), each of which deals 1d8 + 1/2 Str damage. Her bite attack still deals 2d6 + 3/2 Str damage.
- Fire Elemental Taint (Su): The Night Hag's natural attacks (in her natural form or when polymorphed) deal an additional 2d6 fire damage.
- Storm Elemental Taint (Su): The Night Hag's natural attacks (in her natural form or when polymorphed) deal an additional 1d6 electricity damage.
- Ice Elemental Taint (Su): The Night Hag's natural attacks (in her natural form or when polymorphed) deal an additional 1d6 cold damage.
- Air Elemental Taint (Su): The Night Hag's natural attacks (in her natural form or when polymorphed) deal an additional 1d4 sonic damage.
- Ether Strike (Su): The Night Hag's natural attacks (in her natural form or when polymorphed) are treated as ghost touch.
- Shadow Taint (Su): The Night Hag gains concealment when in any conditions other than full daylight or the radius of a daylight spell.
-- N