The turtles are all just a bunch of teenagers figuring out who they are and Leonardo has grounded himself in the traditional culture of his adopted father. So while Mike's practicing his uprock, Raph is reading Society Against the State, and Donnie is mastering portable cloaking devices, Leo is practicing his Kintsugi on the more interesting shards of pottery he finds in the bins outside of Pratt's pottery department. As much as he takes it seriously, his obsession over Japanese culture is still an outsider's fantasy and rather ridiculous, even to Splinter.
He's a bit uptight, but no other turtle holds himself more responsible for his brothers than Leo; this is why he takes his training and the discipline of the group so seriously.
Here Leo practices battojutsu with a crummy kodachi he found in a dumpster in Hell's kitchen.You can get the original 19x24cm drawing on Maruman art spiral paper over on my etsy
These characters were made by Eastman and Laird… fuck if I know who owns them now.