All, finally, I can tell you what it is.
This whole series of concepts was ordered by a group of enthusiasts who decided to gather together and make a MOD for ARK with their piece of map, ecology, Godzilla and monsters. (Blackjack and ...)
They took the basis for their monsters from the Monster Hunter game they adored.
These guys spent a lot of time thinking through the various animals, their behavior and their place in the ecosystem, and I only helped them bring their images to life. Very soon, the 3D artist from their team will begin to create models for these handsome bois.
Of course, since this is an individual project, it had a very modest budget, so they ordered only a sketch poster from me.

If there are those who want to support these guys, here is a link to their patron:
https://www.patreon.com/TheHuntingProject