[spoiler]I'm looking for a manga where the main character was a male he had a limb he lost I think the leg and his sister turned into what they are fighting she ends up as the one of the bad guys with probably no memory of her brother and the mc has like a power most likely based around his leg he joins a group with people like him

Please help 😢

The Blood Reaper

The Six? Except it's the main guy's arm instead of his leg.

No I think she might have killed their parents in like the first chapter as the monster version then became sorta normal she had a hairpin that was important I think

The Blood Reaper

Smokin' Parade?
I've dropped this manga but I kinda remember the first chapters and it fits your description.

Yes this is definitely it thank you

The Blood Reaper