鬼形獣自機の人たちです。

こちらのイラストも収録されているイラスト本が委託開始しておりますのでよろしければ是非
https://www.melonbooks.co.jp/detail/detail.php?product_id=1141818

It's the protagonists from Wily Beast and Weakest Creature.

The illustration book that includes these illustrations is now available on melonbooks, so if you'd like to have it, please feel free to order a copy!
https://www.melonbooks.co.jp/detail/detail.php?product_id=1141818