@Snowave
a wise man once said, " a cat is fine too"
@Myllari123
Leo is most likely an elemental tail and not a behemoth, considering behemoths are super rare.
Unless ofcourse elemental tails are all young behemoths and people are just to stupid to realise, the knowlage about elemental tails comes from the humans after all.
so there is a possibility the humans just have the wrong info witch would open up alot of plot twist possibilities.
But considering there are "tamed" elemental tail it's a bit of a stretch for them to never have been seen "evolving" or growing up in any way.
His second form looks a lot different as seen in previous chapter then his child form so it's not surprising nobody makes the connection if we assume there is a way to make the form change permanent.
But if there is no way to do it, then it's strange that nobody would have seen a behemoth evolve.
Regardless we can presume that he does grow up in some way considering he have a "child form"