The first Ennim, the patron of all others, was wrought from a stretched and filled dwarf. Many Ennim's features show this origin.
The first Ennim's four wives came from the Buffalo, the Lion, the Jackal, and the Roc. These wives mated with the first Ennim, and their children were monstrous, but had features of both parents.
There are many Ennim who resemble mostly dwarves with features of the four mothers mixed. There are some who resemble one of the four mothers more than their father, and are considered of purer blood than most.
There exist many who lie on each portion of the spectrum between stretched dwarven features, and each of the monstrous' wives features.
It's basically up to you completely. However you like it.