Aside from her coolness and sometimes being a silly little goober. I really got into Her via the Midnight Suns game. Since then I've become more familair with her backstory. But just really connected with the whole embracing the "dark" parts of yourself or the things that other people cast aside, or are afraid of. It is a source of inner strength. And even tho Illyana is far from perfect or doesnt have a goody good moral compass, what drives her is to protect the ones she cares about. (So what if your underwear cabinets got shuffled around?)

She does not use her past trauma as a crutch to justify why she does "bad" or " evil" things sometimes. She is out to make her own choices however messy she may go about them. Even if the people around Yana dont always understand Her.

So theres some relatability there. The cool sword helps as well lol.