Oh! I like action and adventure things! Say we have some sort of mystical!reader (they have some magical powers and are moderately powerful). They're friends with Natemare. So like Smoky boi gets captured, and they have to go to Phantom for help to get him back. They don't like Phantom, and he's indifferent to them. So like at first he refuses to go help save Mare, but after a bit he misses his bro & decides to help. Cue adventure where they solve puzzles and traps to get Mare back.
Oooo yes!
Mystical!Reader mostly despises Phantom because of his “Slavery” magic. They refuse to see it as a just due on Phantom’s part in anyway. Even when his Collected talk to them about it. Saying they dont mind or they enjoy working for Phantom or they have accepted their fate. Since they made a deal with a Demon/Devil.
And they work together to get NateMare back. Mostly Reader does all the work, because Phantom only gets his hands dirty when he needs too. His Collected protect him, fight for him and help the Reader in anyway.
But then, just as they get NateMare back, Phantom unleashes a massive blast of Arcane energy from his cane.Destroying the capturer and collecting all the Souls of those that harmed/worked against NateMare. Shoving them all into a confined space of the smallest glass ball he has. Then giving it to Mare,
“Do what you want with them. My Collection is no place for filth.” And it dawns on the Reader, that Phantom can actually Collect Souls without contracts or deals. But he does so, only to give the person a choice. Even if they were to refuse and give him no power or energy, he only Collects Souls with their consent. And after that, the Reader is a little more accepting of Phantom.