This is... pretty bad, like, really bad, and I'm not referring to the choice of paring since to be honest that's what made me click (I'm a sucker for forbidden romance and twincest, something that doesn't get tackled much.)

You've got the formatting down at least so it isn't hard to follow but there's a lot of times where you forget capitalization, especially with Mito's name, also some phrases in the previous chapters are broken, like they were only written halfway, unfinished, some typos here and there too but not to the point it's unreadable.

Finally, the matter of the Main Character and the way you seem to be handling the romance:
I cringed at his introduction, it was completely unnecessary and only served to confuse the hell out of me, that prologue reads like a parody of edgy wish fulfillment writers and that edgy name doesn't help, part of me still thinks this is a ruse but another knows there are a lot of people here that write like this without a hint of self awareness, irony or tongue-in-cheekness.

In the prologue we learn the MC is a certified badass with anger issues able to take out gangs of 37 dudes with barely a scratch, and is feared by everyone as the "Black Demon" black because he wears only black clothes of course.
This is played completely straight, this is why I can't stop doubting this whole story as something done as a joke.
It doesn't even matter though since after that the character acts pretty level headed and bland like pretty much every generic SI MC, and not like the kind of person who gets angry enough to escalate to physical violence constantly as was established previously, not even an hint of anger at the world for killing him or reincarnating him or anything.
There's also the mandatory "I'm insane XD" character "quirk" where characters question the MC's sanity and the MC likes to think they're insane when they aren't at all.
Insanity isn't cool, isn't desirable, it's actually very debilitating to the point you are unable to live a normal life at best, deadly to yourself and others at worst.
It's annoying, people should stop or go balls deep, there can't be a middle ground.

As for the romance between the twins, what I was looking forward to the most:
Handled in the most creepy and borderline illegal manner possible: mentally 19 year old dude looks at his baby sister and immediately makes it his mission to groom it into being his future lover, yeah, this is totally what I want out of this, so romantic... not.
Out of the handful of ways you could have tastefully handled this, you decided to go the perverted obsessive siscon little sister husbandry route.
I'm out.

love the story and i hope it works with him getting mito as his girlfriend/wife i think it's a wonderful idea for a story can't wait to read more

sigue la historia

I am already waiting for the lemon between the twins

nice story so far but nerf 50 wis skills a little xD

"You're a baby, sucks for you." ...Seems legit.

hope he notices the normal people part or he might get cocky.