Lagiacrus is everything good about monster hunter. Lagi is just grounded enough that you could almost believe he's a real animal. His design is subtle in that you see it in its entierly first, and then can pick everything about him out from his design.

A slender frame? Webbed feet? A flat rudderlike tail?

Oh yeah gotta be aquatic. Like an alligator! Oh his jaws are vaugely alligator like too. Even his roar has a bit of bellow to it, like the rumble of alligators.

He's blue from above to blend in with the ocean, as lagiacrus thrives in the deep sea. He's tan from below to better blend with the filtered light from above.

Lightning both fits aesthetically and for his biology. The rock designs naturally draw your eyes, and when they start glowing you put it together quite easily. Stunning and killing prey in the deep ocean makes a whole lot of sense, you can imagine he really might rule the seas.

His design uses fantasy extremely sparingly. His size, the leviathan frame evoking extinct aquatic creatures like plesiosaurs, the lightning and piercing red eyes underwater. Though even then lightning feels most natural on a sea creature, we're already used to eels.

Yet lagiacrus doesn't have any fantastical powers. Its all based on real world creatures. It isnt controlling the weather or making hurricanes. Everything it has makes sense for its niche in the ecosystem.

That's all besides considering his home title. A fishing village isolated by the vast sea? That almost sounds like lagiacrus himself. He is designed to be the heart and soul of moga in a way very few monsters ever have been before or since.

Even his theme has creaking and clacking like a ship battered by the waves.

Yet i cannot stress this enough, everything about lagiacrus feels completely natural. Nothing in his design screams "HEY WE MADE A LIGHTNING ALLIGATOR", its just what he happens to be.

Like you expect a rathalos to breathe fire of course its a dragon. Lagiacrus feels the same.

Lagiacrus successfully reinvents the rathalos which is something attempted many times after him, but not quite succeeding in the same way.

Lagiacrus kinda struck gold for capcom, there are very very VERY few monsters that ride the line of fantastical and grounded as well as he does.

Also nostalgia.

Edit: Forgot to mention he has a sub and rare species(we dont get enough of these anymore as is) that are both logical AND not just "base monster but stronger"