While Haruki stayed in the Chimera nest, the rest of his companions weren't idle either. After Monad relayed their liege's orders, Raven and Avon quickly called for the mind-controlled Carlos and the slightly Corrupted Paul.
Paul felt there was nothing wrong with abruptly betraying the Shifting Sand for Haruki and the Lust Demons. He was already exhausted at the perceived inequality that prevailed over Human societies, struggling at the bottom with no hope in sight. He already did shady things in order to survive and his allegiance to the illegal guild was only established for the sake of mutual benefits. Add to the fact that he had no voice in even the operations he had great contribution in, the dissatisfaction grew big enough to circumvent his fear of the legendary Demons.