150% damage to undead refers at weapon damage , same as 50% damage vs necrobots
churel is an broken oskill that deals crapy damage . too bad it looks so nice(
like many other oskills) , else it would have been a great spell , and we can't have an efficient build arround it . the skill is often failing to hit opponents , that's why i said it is broken . somehere like 25% of the time it misses the targets . + it needs dedicated gear to deal close to decent damage (it needs support skills/buffs to be somewhat efficient) . at this point is far from being a good mid-end game skill . iirc someone tried to make a build arround it , then realised it failed (check the guides forum:
viewtopic.php?f=40&t=1627 )