The Void Reaver is the final boss in Hardcore Mode. It moves at an extremely slow speed, but it has an extremely high amount of health, higher than all other enemies in the game except the Nuclear Monster.

The Fallen Swordmaster is a major boss that only appears as the third boss in Hardcore mode. It was based on the Swordmaster from the SFOTH Event. This version, however, has over three times the base health of the Swordmaster.

The Umbra was the final boss of the Solar Eclipse Event. It had an extremely high amount of health but it had an extremely slow speed.

The Fallen King is the final boss in Fallen mode. It also appears as the fourth major boss in Hardcore mode.

The Molten Boss is the final boss in Molten mode. It also appears as the second major boss in Hardcore mode.

It has very high health compared to anything that spawns before, but moves very slowly to compensate. In addition, it can stun towers and damage units by performing its Stomp ability. It can also perform its Grave Digging ability which "unearths" multiple enemies. These enemies depend on the mode that the Grave Digger appears in.