Eauval occupies a unique position not seen in any other Chapter. This is chiefly because all other Chapters are duff and don't seem to realise how cool dinosaurs are.
Because that's what Eauval is responsible for. Dinos. Big ones (Whopping Gigantoburgersaurus), little ones (Ickle Bicklesaurus), predatory ones (Grr Argosaurus), useful ones (Damned Tsetseflyhuntosaurus springs to mind, or Hey Scratchmybackosaurus) and very, very strange ones (the most memorable of which is the remarkable Spicus Jerrivickimelbeemelseeyemmasaurus, which has five heads, none of which can sing).
Eauval loves dinosaurs. He would have to, I suppose. His quarters are decorated with pink dino wallpaper, his office filled with little furry dino toys. He's the ideal man for the job. He even mucks in and cleans out the Triceratops cages when it needs doing.
In battle he rides on a palinquin borne by two specially bred Brontosaurs, Rene and Cheri, and fires the Rangenstaatdes, an ancient and quite wobbly stand-mounted autocannon.
He also wears the Tricaid Armour, the prototype for the Armour of Krenn, which the Commander has got at the moment. The boss always gets the best stuff. Typical.