It had a lightweight and slender build unusual for a predator of its size and could probably race across the landscape at higher speeds than other large hunters. It was very closely related to its contemporary Bahariasaurus and they may in fact be the same genus if Deltadromeus is a subadult form of Bahariasaurus.
Stretching up to 7.9 meters (26 feet) in length and weighing 1.5 tons, Deltadromeus was quite big and strong and use wit, power and speed to subdue its prey.
Since its body design is that of a runner, it was most likely warm-blooded. It was likely covered in scales or bumps rather than feathers because it was a member of a more basal theropod family, closely related to Allosaurus and Ceratosaurus and it would not need them as an adult since its own size would likely have given it gigantothermy.
Its gracile and relatively fragile frame is not suited for fighting and it probably lashed out at the prey with its vicious claws and teeth, slashing the hide and flesh like an axe until the prey died from exhaustion, blood loss, shock or a combination of the factors above.