Mr.L

Luigi was Mario's younger twin brother and they lived together and went on many adventures together, however, several undisclosed events happened that led to Luigi's death when he fell into the lava. Mario would spend his days tormented by what had happened and eventually, became emotionally wrecked because of it. After going through World 1-1 of SMB3, Mario broke down crying at the same moment he then reunited with Luigi only to watch him warp into a monster and devour Mario's head. Despite having died, Mario would reappear, due to his extra lives, but then soon enters grotesque scenery while being haunted by the ghost of his brother. Soon Luigi will tell his Mario to go to Bowser's castle to rescue the princess to finish torturing his brother, implying that he killed her. Mario will enter the castle where there are several Mr. L around him to then be thrown by the real Mr. L, Mario begs Luigi to forgive him before L throws him into the lava, ending the life of his brother. Mr. L then jumps onto the screen to tell the player that it's too late to save Mario. However, even after exacting his revenge, Mr. L's thirst for torment was not satisfied.

Now he comes here.