Aural decoy and undead rapport are seriously the best spells in the game.
on a side note: I did some more thinking and I found a few more connections.
A) The sword that the protagonist Guts wields in the early days looks the EXACT same as the ultragreatsword known as the "greatsword".
B) Both Dark Souls and Berserk have a big theme on being manipulated and controlled, and they revolve around no-win scenarios.

This is very interesting to me.