I BEG you, please don't write Kacchan as Kaachan.

Honestly, this is SO WEIRD. Look. Katsuki. Ka-chan (-chan is a term of endearment). Ka-chan=Kacchan. If you want it in hiragana, then か-ちゃん➡️かっちゃん. Kaa-chan on the other hand is a more casual way of saying Kaa-san, aka, mother. Kaachan just looks like "mother". Even writing Kachan isn't so bad but Kaachan... pretty please, don't...

....Oops rant