Someday when I have a bit more time, I might try to make a cleaner version. Regardless, Happy Birthday Thirteen!
(Any excuse to draw the hero teacher’s in casual clothes is a good excuse)
Based on the light novels, I have a personal head canon that Thirteen has a Bonsai. Sorry for the lazy background.
A redraw of Thirteen’s face reveal in my style. Until hk reveals otherwise (and actually maybe even then), I am going with reddish brown hair since the most recent photos of blackholes have red rings from particle friction. I am aware I am very late on this one.