Before discussing the assume undead form, what about Dromacus having polymorph self? It can be reasonable. We can get ~100 yards from the village, he turns into a dragon and carries us from there. He can buy this off as 1. leaving massive impression on the village. 2. being the key person in our operation.
IF not we can just go, try to cover our tracks as best as we can and if they follow us tomorrow Ke'Sha will just shrug and say "I found them this way."
Now about assume undead form:
Of course he has it memorized.
This is the post after you mentioned it will take forever with the initial spell list I planed to change:
1st: leave as it was before
2nd: take speak with animals instead of spiritual hammer => 20
3rd: Animate dead , Negative plane protection, instead of Life Drain and Aid => 60
4th:
assume undead form x 2, Instead of 2xgenius => 80
5th: animate dead monsters x2, slay living, instead of dispel good, Air walk, Imbue undead with spell ability => 150
5th-7th: I need the changes for the project...
Now without being too petty
I'm quoting some parts of the descriptions and give them interpretation that I think is fair:
This spell enables the spellcaster to assume the form of an undead creature, with all of the attendant abilities...
...any type of undead they are familiar with of 8 HD or less that they could possibly turn if of six levels lower in experience than their current level...
At level 11 you can turn all. Undead not in the common table are 'Special'
They are familiar with doesn't necessarily means they have to meet it. Ke'Sha had travelled and learned a lot. He is focused on undead. Everyone likes dragons. There is very good chance he met few small ones and read a lot about the process of creating undead. He is after all high priest of the Lord of the Undead. He has divination spells and the devotion to learn about them. I'm familiar with these dragons and I'm not even religious not to mention a priest.
The only difference in abilities... no victims can arise as undead
And very important:
The material component for this spell is a small piece of bone or flesh from the body of being who is now undead.
It doesn't say it have to be a part from the creature you want to turn to, just a piece of something who is now undead. Like piece of the trolls, or the skeletons or Ho & Rror.
So I think it can be done fairly according with the spell description without stretching it too thin or giving it improbable interpretation.
Having said that, it is a strong spell, I admit. But others in the group have great powers too.
Having said that a second time... I'll understand if you want to limit this ability, even that I don't think it interferes with the game, consider for example the polymorph self mentioned before. You can turn to a dragon and have all your spells available. Here you get special powers of the creature you turn into, but you turn only into 8HD beings and can't use your own spells during this time... So it is not THAT much more powerful (if at all). It is different, variable, interesting... It is nice to drain levels. But you also get the vulnerabilities of the undead... so all in all it is strong and yet balanced. Also consider polymorph other that can grant the creature the actual special abilities and any HD, and this can be even more powerful way to create OP allies.
But if you still think it is OP, I'd rather not to restrict it only to the common simple undead, because then, under 9HD they are pretty simple.
What about having 10 or so interesting creatures that I can choose? 1 or 2 dragons. 8 other specials? from the hundreds of special undead exists...
