I'm looking for family members since Kiyoshi will have a pretty large one.. His dad is a yakuza lawyer and idk if that would be anything of interest but if you'd like, Kiyoshi and Mikazuki could be cousins through their father or half-brothers through the same mother (though I put her as an ikebana master she could have changed profession after she broke contact with Kiyoshi when he was four; though he did meet her and some child of hers once in his teens after that, and saw her/them from a distance a couple times).