Hey guys!

Is there are some sort of a summary for the units? Which shows where you can get which unit and in what you can promote them?

Greeting
Bananchen

http://eador.com/B2/viewtopic.php?t=3470

Ok thanks nice tables.

But where you can get a e.g. Lich?

Is there any hint for special creatures to obtain them?

Lich is one of the few which are impossible to get - he is Level 5 unit, there are no slots for them.

AFAIU, depending on the unit, recruiting it requires
1) a specific building in the castle
2) an "egg" (and often/always also a specific building in the castle)
3) a contract scroll
4) a ritual or ritual scroll
5) a spell cast during combat (for some undead units)

(I'm still learning how to navigate the var files, maybe I can try to answer more specific questions. As Gremlion said, level 5 units cannot be recruited into a hero's army.)

Regards.