Interesting, so Mephisto is one of the few people that recognizes that Iruma took action before even the schemer Baal could. Even if Mephisto was on Baal's side before, I think he might actually mean it when he says he's Iruma's ally since that display probably impressed him more. I could definitely see him being in with Baal, especially since Baal presents main character energy too, but the Iruma might have stolen that spotlight in Mephisto's eyes if I am correct, at which point he might be more of a double agent now and biding his time to take action. That being said, being Iruma's ally also doesn't guarantee that he is going to actually be helpful since he could have his own interpretations of what is "in Iruma's best interests" 🤔