Asmo changes how he refers to Satan depending on the situation.
Satan: *comes downstairs late with disheveled hair, looking tired and grumpy, glaring at Levi* Mammon: What happened to you? Satan: *continues glaring at Levi* Levi: ...Look! Run Away with Me Neko-Chan seemed like the sort of story he'd like! I didn't realize that he wasn't emotionally prepared for the finale! Asmo: Levi! Did you recommend our baby brother another heartbreaking manga?
Later the same day...
Asmo: I just got off the phone with my agent. I'm going to be on the cover of Demonia Monthly! Satan: Again? Asmo: Mhm! So you'd better buy it! Satan: I see your face every day. Asmo: You really aren't going to support your adorable little brother when he's trying to achieve his dreams...?
If he thinks Satan is doing something cute or funny or endearing, Satan is "my baby brother", but if Satan is being a jerk or ignoring him or acting high and mighty, it's "How could you do this to your precious little brother?"
