The Endo-Upgrades are types of equipment sold by Mendo. They are used to upgrade the party's defense in the game. There appears to be only three of them to buy.
- Reinforced (Cost 250) - They boost up defense by 10.
- Steel (Cost 1,500) - They boost up defense by 20.
- Titanium (Cost 9,000) - They boost up defense by 100.
Total cost to buy all the Endo-Upgrades: 10,750
- The Starter Endoskeleton is Endo-01's body, and the Reinforced Endoskeleton is Endo-02's.
- The Steel Endoskeleton is Endo-01's body as well, just enlarged and recolored.
- The Titanium Endoskeleton is also Endo-01's body, but with 3 extra buttons, hint of ribcage, enlarged, and recolored.
- Mendo himself has what appears to be a recolored Steel Endoskeleton.
- Because the player can only have one Endo-Upgrade equipped at a time, and there is no way of switching back to one endoskeleton after equipping another, it is advised that the player never purchases an Endo-Upgrade worse than what one already has.
- The Titanium Endo blocks all damage from physical attacks. (Bosses excluded)