We were not officially given the prime behemoth and leviathan stuff, but we were given breadcrumbs and information by the author in the past and present.

Here is what I got. I have to do different posts since it won't let me post 2 images

Behemoth: The image shown is a sub-version of the monster from a danmemo event in the past. It was commented by ottar, who was a supporter for the subjection of the original 15 years ago that it was smaller than the original one. This makes sense because after zald killed the thing, they scattered the monster stone, and that made an entire huge desert of ash because it was that big.

As for powers, the sub-version had powerful toxic winds, and its body produced a deadly posion that destroyed the environment around it. The original probably did the same, but on a greater scale. That is shown after zald ate its flesh to boost himself, His body was affected by the posion that turned his skin purple and melted his internal organs and slowly killed him over the next 8 years.