Devil Yoshi is a joke page, which means it's not meant to be taken seriously at all. Joke pages are typically silly dumb ideas that'd never work or ideas that aren't meant to be taken seriously at all
Devil Yoshi is the Golden Freddy type animatronic of Five Nights at Yoshi's.
Sometimes in the Back Cellar, the spare endoskeleton will be replaced with a yellow Yoshi suit. If you take down the monitor, Devil Yoshi will appear. To get rid of him, simply put the monitor up again, and put it down. If you don't, he will jumpscare you, and crash your game.
Devil Yoshi is a yellow winged Yoshi with red eyes. He also has dark blue-purple ish wings, green boots, a light blue saddle, With a big, blue-purple ish set of eyelids and belly.
Devil Yoshi was the original mascot of Yoshi's Pizza Parlor, known as Yoshi's Playground Pizzeria, until the building was sold to the current owners, the company of Dino Government. He was then stored in the Back Cellar, meant to never be used again. Until a certain day, he was un-discovered, until Phone Boy found him and set him free.
Emy - Emy asked out of curiosity if he could teach her how to fly. He did so, and ever since it worked, they've been close. Not too close like Phone Guy and the night guards, but close enough.
Boo - Boo and Devil Yoshi are the only paranormal animatronics at Yoshi's Pizza Parlor if you exclude any remodels of them and injured forms. They constantly compete to see who can kill the guard first, close or near, dead or not, they keep going until they both drop to dust.