Evil in the flesh, made from the malice of the world which eventually spurt to life in the form of Janemba. Formerly a leader of an organized crime syndicate in Hell, he has reached the world of the living to cleanse the souls of those who live and turn them into monsters.Know more
Janemba itself is simply an entity made of evil. The malice of humans concentrated into a single being that desires destruction and the end of all. The physical form of Janemba, at least their most powerful one, is from a Hell Demon and criminal boss. He was specifically made after a young ogre responsible for watching over the Soul Cleansing Machine fell asleep and allowed the machine to become unstable and explode, releasing the evil souls within and turning the teenage ogre into a massive being inhabited by Janemba.
As it happened, Goku was participating in the Other World Tournament, close to the Soul Cleansing Machine. While fighting Pikkon, they are interrupted by the massive Janemba. Goku, excitedly, goes off to fight the demon while Pikkon stays behind to break the barrier Janemba made. Throughout his fight, Goku needed to unleash his Super Saiyan forms to match the strength of Janemba. He smashed him nearly to a pulp with that power, but all that helped Janemba form a new, stronger body.
Most of Janemba's value as a competitive character comes from his zoning abilities, which doesn't follow the common elements already in the game, thus allowing competitors to play around with some interesting results. For starters, his slow tracking Ki Blasts and sword specials can break projectiles. Add in his Dimensional Hole, and there are very few reasons to try to best Janemba at a distance; he is just too powerful. On the other side, he is a very big character on screen, and his hurtbox can prove hard to play around, secondarily the lack of anti-air materials can also limit the control he has of air space.