The Time Bear is a late-game "antagonist" of Wall Destroyer. It's a mysterious being that appears to be extremely powerful, as it is only mentioned when the player plays with time itself, when resetting the game.
The first mention of the Time Bear occurs when the player resets the game the 2nd time. The Necromancers use their magic to steer the Bear in another direction, warning the player to not use this tecnique any further. All the magic beings, even the demons, are afraid of this Bear, telling the player that it's coming, and once it does, bad things will happen. As the player ignores the wizard's warning and continues to rewind time to accelerate the destruction of the walls, the players allies start to ask the magic creatures about the Time Bear, and all of them just say it's dangerous. After some resets, the Time Bear aparently starts to proceed with it's unknown purposes. One of the "agents" went crazy after seeing the Bear, and graffitis started to appear in the player's headquarters, with 2 agents requesting to terminate the Time Rewind project.
When destroying the End Walls, in a scroll says the Time Bear and the Black Obliterators are the 2 absolute powers in the universe, infering that only the Black will be able to stop the Bear's fury upon the player and all his/her allies.