C-G5 is a android hybrid created by Dr. Kikky from the alternate timeline where the Dark Bosses took over the Earth with an iron plush fist until The Comedic Duo Y/n aka SMG5 and Mario along with Tails Doll, Bloody Bunny and Mumu managed to defeat the Dark Bosses and fix the timeline.

However, Dr, Kikky managed to create an android hybrid known as Cell SM-G5 aka C-G5 made with the DNA of the entire cast in the series including Y/n aka SMG5 and  Perfect Cell as the data from the alternate timeline was sent back to the past abd transferred to one of the containment chambers at one of Dr. Gero's abandoned labs where Perfect Cell was born as Imperfect Cell as he became the first android hybrid and a very powerful one at that.

He may resembled Imperfect Cell, but he is both agile and strong as his power levels are both similar to Y/n and Perfect Cell's power levels combined, making him a real formidable opponent.

It's also known that he is the brother of Electro Slice as she is one of Dr. Kikky's best experiments as it is his mission to give ES the message that Dr. Kikky left for her as he and the rest of the Dark Bosses are still out there alive, giving ES a chance to reunite with Dr. Kikky.

Eventually, C-G5 soon later became a member of the F.O.E.S. (Force of Evil Society) as his new task is to force the SMG5 gang to the join the Dark side.

He also smells like Elderberries since he also has Smiling Critters DNA as well.

His favorite drink is Sprite Cranberry.

His tail is much more different than Cell's tail as it has multiple features like draining energy from living things and machines, create EPM that can create a massive blackout around half the world, use it as a syringe to extract blood, drain energy/Life force, inject serum into his targets for both offense, medical purposes and make himself more stronger.

He can also change his body heat and use camouflage like most reptiles.

He is very intelligent like his creator/father figure, Dr. Kikky.

He is also immune to tons of diseases and infections and he also immune to the Pibby Corruption, FNF Corruption, and Baby's (Dragon Ball Z) body possession virus.