Okay but a wholesome headcanon for grown up deku:

And is a fully inside cat and Deku and his pet just have respect for each other like he'll just sleep all day and Deku will come home make sure his food and water is full Deku will give him pets and things but never meoWS without a reason doesn't attack Deku jisy a massive fluffy graceful cat that cuddles with Deku and follows him around and things
But is just a quiet
Deku will sometimes ask him about his day and The Cat will just nuzzle his ankle and Deku leans down and scratches his head "a good day then? Didn't make a mess of my sheets while you slept?" Cat squishes his tail
"That's my good boy" he hums and puts his bag down to do his thing

Yes! And so how he got - the cat- was there was someone trying to throw the kitten away and Deku saved the cat and he was: hey does anyone want thus free cat does anyone: um?And then he looks at the kitten like: I ...have a cat now? And he just puts -the cat- on his shoulder and he just nuzzles him until he gets home and he puts down the cat -welcome home then cat-
Deku will be training on the thing where you lay down and push weights up and down and -the cat- will jump on his chest softly and just his eyes looking into Deku waiting till he meets his eyes calmly and Deku puts down the weights like- okay you can have pats- and they cuddle