The rules for cursing in Black Crusade seem really interesting. It's nice that someone can be going about their business and a person that the group has mistreated suddenly starts hexing them from across the galaxy. A good Bind against them will just wreck a Psyker's day.

Send in Bloodthirster, that has an axe with another Bloothirster locked inside. If you kill the wielder, the other bloodthirster erupts from that axe, and has another axe with another bloodthirster insinde! Infinite combo!

Really? I'm no expert on modern fluff, but back in the day BT no. 2 had no axe.