Ruin is from a alternate dimension where Sun and Moon merged together creating Ruin or Eclipse is his real name ( people call him Ruin since there's another one named Eclipse as well )

his dimension is gone and in it a virus spread made by Ruin's Creator which spread through the animatronics yet Ruin was the only one unaffected but he did carry the virus

when his Creator found out he forced him to kill a child and do his bidding else he would die

so for years Ruin pretended to be a insane virus infected animatronic

- he found his way to The Sun And Moon Show dimension where he still acted insane but he had a plan

it worked and when Moon ( now known as Nexus and is dead ) inserted the virus cure Ruin would pretend to be cured

- he brought back BloofMoon when he was pretending to be insane and then he in secret brought back Eclipse to distract Sun and Moon while he worked on something - when he was outed, he revealed he built a device that'll destroy every Creator that's in the Creator Council or alive and it would ensure that a Creator will never exist again

- it worked but trillions of the fallen dimensions died including Solar ( Sun's and Moon's brother from one of those dimensions ) - everyone doesn't trust Ruin because of that

Moon would become insane from this and on his path to try to bring Solar back, he would almost kill his sister Earth with Star Power but thankful Ruin protected Earth, Puppet ( a friend ) destroyed BloodMoon and Nexus got sent to Space where he was found by Dark Sun and joined forces with him

the Original Moon would return ( and he doesn't trust Ruin )

Ruin is caught by Nexus and forced to work with him but Ruin in secret planned for his demise

( also Solar by now returned, came back to life thanks to Eclipse who he , Puppet , Foxy and FC moved to another dimension )

Sun killed Nexus with his fire magic but Ruin put a bomb in Nexus which really set it off ( no one knows this excepts Eclipse and Puppet )

after that Ruin would go to the dimension where Eclipse and Puppet reside , which was made after the 5,123 got destroyed

there's differences in this dimension

Ballora replaces Chica

Foxy replaces Roxxane

Lefty replaces Freddy

and Monty is a woman

( Ballora and Monty are also a couple )

in Ruin's eyes though, he sees things like how they are in other dimensions

Ruin wants to stay since he inadvertently made this dimension

Lefty, the Foxy of this dimension who the other Foxy replaced , Ballora and Sun want Puppet gone because of her powers and only on a If she uses them

Ruin doesn't agree with this

In his repaired model, their previously washed-out yellow crescent and torso is now white. The other half of their flaceplate is a deep indigo. They have a red swirl on their right cheek and a blue one on their left. He has a bright blue right eye and red left. Their red frills at their neck and waist resemble Sun's.

They have blue pants with yellow stripes, appearing cut in a pattern at his ankles. His shoes are different colors, the left one being red and the right blue. His hands are also different colors, the right being yellow and the left blue respectively.

They have three rays each on both sides of their head, and he wears the same nightcap as Moon

Ruin speaks in a British accent

Ruin loves tea

he likes singing You'll Be Back from Hamilton