Indirectly manipulated through his Holier Than Thou attitude. The Disney Acid Sequence during "Hellfire"? Those were the Friends, pretending to be judging Frollo for his lust. In fact, they were hoping he would go on the destructive route he later went on, killing people left and right giving fresh soul-fodder for the Friends. Plus, once he died, they had a new soul. That gargoyle at the end was no hallucination, but rather Chernabog collecting what was his due. That said, the Friends weren't responsible for making him a Complete Monster, he was that all on his own. The Friends just gave him a small push in the ‘right’ direction. In the end, though, Chernabog realized how much darkness was in Frollo's heart and decided to fully lure the judge to his side, which explains his allegiance to the villains in Fantasmic. Nowadays, Frollo serves as the Friends' morality judge, deciding whether certain clients go to Tartarus to be harvested when they die or to serve in the Inner Circle in minor positions.