Hello. I`m playing with paladin and I did not build up enemy estimation skill, so does anybody know which is best weapon to kill spirits and that guy FaeDarlion or something like that. I guess he is undead but I dont know if there is weapon with undead dmg bonus.

I'm honestly not sure if the game differentiates between damage types, i.e. piercing/slashing/bludgeoning/etc. So as far as physical damage goes I think it's all lumped together. In some games bludgeoning weapons work good against skeletons for example. As far as magical damage goes undead are usually immune or at least resistant to poison or disease effects. Again not sure about this game.

However, I do know there are weapons that have +percent to undead/animals/all damage. In theory the former would help. But the spell exile (unfortunately only available to priests) is the best attack I know of against undead.

There is no way to kill ghost, undead monks, shadows etc. efficiently with physical damage caused by normal weapons. Only elemental damage can harm them seriously.
As a paladin I suggest to rely on signs against these types of enemies because your magical abbilities are limited. High class signs (the ones with four points) are very effective against all sorts of enemies, but they are costly when often used. You can buy signs at every friar/priest.

Hello again?

How to kill undead knight in galtzbur cemetery that want to kill executioner from 2nd town?

You have to fight him first and flee after he said that he is immortal. If you manage to escape the dungeon alive you can go to the herbalist woman and ask her about his immortality. Then you have to fetch some holy water and return to the dungeon to defeat him once and forever. ;)

Thx.