The Mighty Aroo
Nemesis: Martian Manhunter
Other Major Foes: Zook
Appearances: One comic story
Powers: Flight, durability, destructive energy beam & flamethrower.
Bio: Released by the Diabolu Idol-Head to protect it and the egg of the Chulko. Caused destruction until it vanished under unclear circumstances.
Win: Genie of Gensu (3-1)
Lose: Iwangis (1-4)
Other Major Foes: Jimmy Olsen
Appearances: 30+ comics and a cartoon appearance.
Powers: Giant-sized; Kryptonite eyebeams, super-strength and durability.
Bio: A monkey sent on a space mission who became exposed to meteorites containing uranium and kryptonite, physically altering him.
I don't think kryptonite rays are going to do anything to Aroo, who also has a flight advantage. On the other hand, Titano is sometimes resilient enough to throw down with Superman, while other times is just a big robot that collapses under super strength like a beer can. Could go either way.