Questionable Questing

So this company or government, or whatever is trying to abuse the internet and celebrity culture to super charge its magical girls and this is a test bed for that.

Is worship just for Idols or it work for infamy too like John Wick's reputation?

I think it works both ways, but since worship isn't dependent on any one emotion just the strength and amount of people involved, its a lot easier to rise a idol than it is a John Wick.

So our Devil man, say he likes his work but has surprised longing for a family mixed in with his depravity. A non sexual man turning sexual?

As he corrupts the girls he becomes corrupted

Honestly haven't got much of a clue on what to do with the MC. Just dark sketchy past, a deep need for control born from fear's of his devil powers going out of control, under strict supervision by his boss despite several years of loyal service because of how dangerous his powers are. Other than that, not much else.

Anti social person forced to socialize and open up. More collected making threats or doing business then with living with four girls and speaking to their moms

Discovering he really likes the power imbalance of being their manager and pushing boundaries.

The mom's could be retired Magical Girls, with Magical Girl powers wearing off over time and acts as a handy excuse for why teenager are needed to save the world.

Fans create fan art and comics and stories of the girls enslaved and broken and depraved. Our Devil scans this as part of his manager job and filters their social media feed but it awakens something in him.

The girls do get power for being fetishized as sex symbols and he wants that power. Power over them.

A career man discovering a passion for once in his cold brutal murderous life

I'd have you have milf magical girls but the question is to keep the power pulls in conflict with Devils and other Idols. The parents didn't want that and let their powers fade. Others don't

I like that. An ice cube learning how to love and be a bit of a softie, but also that he really, really likes seeing his girls tied up and worshiping him.

I also really like the idea of all the Magical girls having some flavor of daddy issue's and Mr. Devilman taking over that role for them.

It's a mix of growing enamored with emotional connections but also addicted to extreme domination and training sex slaves out of the girls and their mothers. Turning them into a personal porn stream harem

But also trying to hide it from the company and the internet, since one of the biggest appeals of Idol's are the supposed friendship and seemingly romantic para social relationship they cultivate with their fans and them having a boyfriend and a life outside of being an idol would ruin that, thus running the amount of worship they receive.

Necessitating a private sex dungeon.
Who are our four girls and their moms? Based on RWBY or other things?

I was just going to play the above completely straight, but that was before when there was no magic powers and this was normal if incredibly shady and using experimental body modification, Idol company.

I like the idea behind it. They think they have a lawyer but he's also a assassin and soldier agent

Plus the idea of the goofy excited sleazy lawyer on the surface hiding a very complex and dark figure underneath, and the girls slowly discovering that.