Soul Stealer

Soul Stealer is an enchantment from Soul Shards that, in pre-1.5 versions, can only be applied to the Vile Sword, post-1.5 versions allow the enchantment to be added to any weapon or book. It increases the number of souls obtained from killing mobs. Only 4 levels can be obtained on an Enchantment Table; level 5 can be obtained by combining two level 4 swords or books on an Anvil.

You can also obtain this enchantment on a Book.

Level of Soul Stealer	Souls trapped per kill
0 (Native Vile Sword)	1
1	2
2	3
3	4
4	5
5	6