Lol. True.

Is limbo those who died during limbo?

Limbo is basically reserved for the people who lived out virtuous lives but were not baptized or truly knew God. It was essentially the middle-ground between Heaven and Hell.

Keep in mind that nothing in the Bible indicates that there are levels of hell. According to what I have found, the levels of hell idea came from the Italian poet Dante Alighieri, who imagined that hell had an elaborate system for sinners in his religious comedy: Divina Commedia (The Divine Comedy).