Ares
Powers: As an immortal god, Ares possesses vast strength and endurance. His physical attributes are superior to the majority of Olympian gods. He is able to lift approximately 70 tons. He has virtually inexhaustible stamina, not tiring appreciably after any exertion. Like all immortals, Ares cannot die by any conventional means. His life force is beyond the reach of mortal injury. He can be wounded in battle, but his godly life force gives him incredible recuperative abilities. He can heal from penetration wounds (such as by knife, sword, or bullet) in anywhere from minutes to hours, depending on their severity. Only an injury of such magnitude that it incinerated him or dispersed a major portion of his bodily substance could kill him. However, in that case, Zeus or one of his fellow gods may have the power to resurrect him.
This is reported from immortalthor.net
Ares is also able to fly, and that's another major advantage.
With his weapons, which are in the durability league of Mjolnir, cause made of adamantine, Ares can surely manage to damage Hulk, and Class 70/75 tons of strength is enough to slice and behead Hulk.Wolverine can do it, so according to Marvel, Ares should be able to do it as well.Like Thor should own Hulk mostly, Ares should be able to kill him, with more fatigue, but still able.