Varanus obor is a member of the subgenera Euprepiosaurus.
The coloration is of the dorsum is dark brown, charcoal gray or black. Some single tan or pale yellowish brown scales are dispersed over the back. The front of the facial region shows some orange or orange-red markings. The coloration ventrally is dark gray with several pale areas. Also some irregular incomplete transverse bands are visible.
The throat is gray-brown, with several white markings, which are arranged in 4–8 transverse patches. The coloration of the mental region is usually white, sometimes showing an orange color laterally.
Tail is strongly compressed distally. The coloration is dark brown or black and shows 17–20 indistinct, narrow pale bands. The length is about 1.5-1.7 times the SVL. 119–134 scale rows are around midbody. The total length is up to 120 cm.

The distribution of Varanus obor is restrictest to the small island of Sanana in the Maluku Utara province (the north Moluccas). The Sago Monitor reaches the highest densities in coastal sago palm swamps. In this habitat individuals were seen digging
through decomposing palm trunks in search of beetle grubs (WEIJOLA & SWEET 2010).