What if she was sex worker who slept mostly with miners.... And one of the "usuals" always brought her his safety helmet and she was putting it on. And maybe once he left it occasionally (and died later 'cause fate played bad trick on him?). He could actually be around Kilkil's age and be really nice guy (maybe smth like her boyfriend?), so she kept the helmet? Idk. Just silly thoughts at work
child labor is pretty common in mines, maybe this poor bastard actually lived to majority (15 or 16) - and his coworkers took him to a brothel to celebrate - and thats how the two of them started seeing each other? She could still be underage (14ish?) but she's been doing this for a while and no one really bats an eye. She kinda likes being his first and he really is so sweet and shy. She gives him discounts for being sweet and treating her like a person.
Oh she's gonna give poor guy fake mommy issues with her doting and experience
eh - he aint gonna live long enough to worry about it~ maybe the helmet he left behind was his 'kid' helmet - being an adult now means he gets adult gear - and its old and on the small side, doesnt' really fit him so well, but Killer is (and always will be )on the smaller side, and she tried it on that first night after round one, and he called her cute and she ended up keeping it. kidd is jeally and he has no idea why, but he also disapproves of killer with sucky gear and starts repairing it behind her back. she's not pleased with him messing with her stuff without asking, but he does a good job. by the time she's using it to fight, its a Ship of Theseus situation, having been repaired and upgraded so much only the idea of the original is still there