Yeahh the gap pretty big
Don't forget that his original age is 40 years old. So, I don't think its bad. And since they are based on animals, they age quite fast. I may say that he is much older than them.
Chika's case may be somewhat excusable but basing on how the story progresses from here on I can say this manga is actually quite problematic.
*Spoiler* *Spoiler* *spoiler*
It gets worse with their children.
His first borns will be twins, a black lion and a human, both are animus (omega in omegaverse terms). The black lion gets together with the half-dragon bodyguard (new character) who basically raised him, and the human child gets with his cousin Theo, who's been eyeing him since he was born. His third child(human) gets together eith a 200 year old dragon who basically helped birth him. Plus, even after their children have grown up chika's body forgot how to, so he still looks like a child at mid 30.
Okay, that was insane. Tg, I didn't have to read it. Thank you for your explanation. I was okay with their situation but not acter that.
I realized I unconsciously turned off my brain when they mentioned their age(⊙…⊙ )