I love this story and that's saying something cuz I'm not a fan of MC being a "villain" or a bad guy not saying I'm a fan of goody two shoes I'm more of a fan of anti-heroes more of the neutral ground neither evil nor good
why don't you make it so he can make life sword or fire that just troves around or lightning. he doesn't have to have a clone stab some one if it is not a condition. you can also meas with he's perception of time or take away all of he's senses.
get to have him chrollo lucifer hatsu that copies other's hatsu but with different set of rule and condition then chrollo ... it should be possible because both mc nd chrollo have specialist attribute ...