User blog comment:KillRoy231/What Dean should have done about the Mark/@comment-1031724-20160921044542/@comment-188.37.49.141-20160922095928

Yeah, make who's arguably the most powerful witch alive virtually immortal so she can give in to the Darkness, gain unlimited power, and tear the universe apart. Or a Leviathan, so it can eat everything.

As for Death, remember, he was still bound at the time, and he doesn't have the power of foresight. He didn't think Dean would turn on him like that.