|HIT * 95%||EVA * 33%|
|Attack Element: Physical||Scared * 50%|
|Paralysis * 50%||Sleep * 50%|
|Stun * 50%|
Jonathan is a pale, thin Joy Mutant with messy black hair and stubble, dressed in a white polka dot dress. He was enslaved by Slave Lord Jim before he went missing. After defeating Jim, Jonathan appears outside his former slavemaster's house as an enemy the player can fight. It is not known whether he was already a Joy Mutant before he ran away from Slave Master Jim.
- Jonathan can be found on Dismal Island after defeating Slave Lord Jim.
An important factor when fighting Jonathan is his speed. He is by far the fastest Joy Mutant, and can outrace several party members. This means that there is a distinct possibility that he will use Fatal Chomp on the first turn, meaning he can perma-kill a party member before they get the chance to attack. There are moves that can counter his speed, such as moves that increase a party member's speed (such as Yazan's Purrfect) or decrease the enemy's speed (such as Carp's Ankle Slash). There is still the chance that his first move will kill these party members before they can attack, so extreme caution and preparation must be used when fighting Jonathan.
- Losing against Jonathan will not result in getting a game over screen, you'll instead be kicked back to the main world with all of your party members being at 1hp. However, any party members hit by his perma-kill attack, Fatal Chomp, will remain dead.
- Jonathan is confirmed to be a Joy Mutant, despite his unique design.
- He has a unique battle sound and death sound.
- According to Austin, Jonathan is based on a story about Jonathan Holmes 
- Jonathan is the only Joy Mutant in the game to not drop Joy.