How do they act around mc in their last form? Are they more sinful or aggressive or anything lik that?
Lucifer : Lucifer prides himself on his self control and he likes to pretend that he has no issues dealing with his more demonic impulses in his true form. In reality, his pride has a much stronger grip on him when he’s like this, making him seem cockier and less uptight. He’s quite prone to showing off, too, rattling his tail feathers and flaring out his wings around his partner, making sure their focus is entirely on him. It’s much easier for them to get a reaction out of him than usual, especially through physical affection. All it takes is a few gentle touches and soft words, and he’ll be purring and cooing without even realising it.
Mammon : Being in his true form makes Mammon’s impulse control so much worse, and it was already bad to begin with. His greed becomes a constant, thrumming need in the back of his mind, impossible to ignore. It makes him very possessive of his partner, filling him with the urge to hide them away, keeping them safe and protected from the outside world. When he’s like this, the thing that makes him happy is just physical contact, and he’s much less likely to act standoffs about it. He wants to be as close to them as possible, nuzzling his beak against their face, rubbing his scent into their skin, and wrapping them up in a warm, feathery, embrace.
Leviathan : As long as his partner doesn’t react negatively to it, being in his true form gives Levi a huge boost of confidence. His massive size, enhanced strength, and heightened endurance underwater make him feel powerful and capable, able to do things he’d never be able to on land or in his human form. While he’s likely going to worry about it later, in the moment, his actions could almost be labeled as bold, feeling brave enough to initiate affection, gentle touches and compliments come from him without quite as much hesitation as usual. If they hype him up, he may even start showing off for them, too.
(cont under the cut)