He is usually the deuteragonist in videos, being Mario's sidekick. His personality wildly varies between appearances, but he is mostly a fruit lover, a coward sometimes and usually a nice guy. He also refuses to pay his taxes, going as far as letting his child die in War of The Fat Italians 2018 and he is shown to be very suicidal shown in a few videos.
Yoshi is an anthropomorphic dinosaur who is a drug addict. He is an ally of Mario, Luigi, and Peach. The reason that he lives on the roof of the castle is because he ate all the food that Peach had. Yoshi, wanting to return to the castle in the video Yoshrooms, tried to break into the castle., and past the events of videos Yoshrooms Yoshi was part of the cast with Mario, SMG4, Meggy, Luigi, Bowser, and among others. His exclusion is seen in the video of Stupid Mario World where Yoshi asks Mario why he does not visit him and Mario tells him that it is because he does not see him when he walks out of the castle and becoming only cameos in recent videos.
Yoshi, like much of the other characters, has a few special abilities:
Near-Invulnerability: For an unexplained reason; Yoshi has somehow endured and survived any and all misfortune and abuse he's been slung: including and definitely not limited to crashing into the castle wall while at the same time, his back was surviving a pressure of over 590 pounds (Wario was riding on him), falling onto molten lava and living, even after being blown up, survived humping a watermelon, falling all the way off a bridge and exploding once again at the bottom, survives having his legs crippled near daily, duels against foes in excess of street level, and, most notably, in Yoshrooms, Yoshi survives getting drugged for over 2 weeks, blown up, savagely beaten up by a fellow Yoshi, crushed right in the stomach (one of the most painful and deadly areas to be struck) by Mario's kart (which can reach averages of 55 MPH in Mario Kart), dragged across the street. He felt all of this, is clearly quite traumatized. It's actually quite surprising what he can live through, granted his sanity from all the trauma is quite irreversibly damaged.