Coach Morceau Oleander is the main antagonist of Psychonauts, though he doesn't appear in the game as much as his partner Dr. Loboto after he is revealed as a villain.
Oleander is the main counselor at "Whispering Rock Psychic Summer Camp", which he runs like a drill sergeant and right from the start is very mean to all the kids. The first level in the game is a battlefield–like training course within Oleander’s mind throughout which his voice is heard yelling insults at the trainees, including the player no matter how well they are doing.
Later, after the campers’ brains start being stolen, it is revealed that Coach Oleander is plotting to steal all of them and use them for brain–powered psychic tanks which he intends to take over the world with. To this end, he is working with Dr. Loboto, the proprietor of a nearby insane asylum, to extract the brains.
Oleander is indirectly fought twice during the game: the first time as “Kochamora”, his avatar inside the mind of a giant Lungfish, who vilifies Razputin’s avatar, Goggalor, and the second time towards the end of the game as a brain in a giant tank.
It is revealed in the final level that the reason for Coach Oleander’s evil is that he grew up on a farm and loved the animals, but his father was an evil butcher who slaughtered all of them. What really pushed him over the edge later was the fact that he was rejected from all branches of the military for being too short (which also reveals that he was never actually in the army despite his personality). The final boss is a fusion of Coach Oleander’s memory of the Butcher and Razputin’s demonized mental image of his own father.
After this monster is defeated, Coach Oleander is forgiven as it it assumed defeating his inner demons has gotten rid of his insanity, and Razputin is promoted to an official Psychonaut.