First of all, you have to realize according to Shinigami I'm particularly vulnerable in his world, where to Arachne I'm her most loyal new follower. Of course, that only covers my own case.

Because Shinigami tides us over with platitudes and principles, but Arachne keeps her promises and gives real gifts. She was going to help Giriko stay alive for eight hundred years. Why do that if she didn't love and reward him? She's even got a brainwashing machine - why not use it on someone new?