It’s still weird coz the majority sees him as a cute little brother for the mc and him, becoming a man (even though he’s old) is sooo sudden like a ghost popping out without notice lmao. They could’ve made it slow and put some scenes where readers could see him as a man and have moved on a little bit of him being a “kid” and not the “here’s the chapter boom magic! he’s a man now!” That’s the reason y majority are so turned off. The scenes where he was jealous look like a child throwing tantrums lol. Like what an actual fuck
Tbh yeah I don't really see it being a major turn off for me because the story already established that he is an adult, just was mentally and physically stunted because he was abused for a long time. It was weird that he popped out of a phucking egg instead of catching up with his age through some self discovery shid though. For me the leopard is less memorable than the other guys and I think hasn't really established his presence at all due to poor writing. They really could've gone a different way but I've read worse like I never abandoned the tyrant where she actually raises the ML, seen him grow up, wiped his ass all that and still see him as a romantic interest.

Javi stated himself he was older than normal he just ages differently from regular humans, to most beasts he’s already an adult just because he doesn’t know as much as an adult should doesn’t mean he’s a child, he was abused so it was impossible for him to reach the point he’s at now…I actually don’t mind him being the ML I assumed he was going to stay a child when I heard him being the ml which made me put off but now that I know he isn’t and that he’s actually a lot older than he’s outer appearance showed plus he’s a hot man?? I’m like “oh okay that makes sense” u can complain abt it all u want but nothing u say will change the ml the only reason why the other story y’all like called “I was born as the demon lords daughter” was changed is cause the ml was literally DOUBLE if not TRIPLE her age and was making advances to her WHILE SHE WAS A CHILD. The mc never did that and while she did see him as a kid now that he’s obviously not she herself realized she shouldn’t treat him like that anymore and neither should u. That dood was a grown man even if u couldn’t see it
This may be a shit take but it is what it is I’ve learned to just make make it make sense while im here, legit just riding the wave and letting the story play out cause nothing I think will change it so I’ve decided to just not mind it and let it happen (plus it’s not every day you get the animal shifter character as the ml usually it’s a mage or someone else that’s powerful)