Blood Rage

When hit, wearer randomly gain short-duration strength and constitution buffs, followed by fatigue.

There are three levels of the rage. Level one last for twelve seconds and improves your strength by two, level two last for six seconds and improves your strength and constitution by two (for a total of four) and finally level three last for three seconds and improves your strength and constitution by four (for a total of eight).

The first rage acquired is always the level three, when it fades, it turns into level two. When level two fades, it becomes level one. To acquired the rage, you need to be hit. So to acquire all three levels of rage, you need to first get level one rage, allow it to fade to level level, get hit again, let the level two rage become level one and level three and then get hit again

When the rage fades, it turns into fatigue which lowers your melee and ranged attacking speed by 50%. Lesser Restoration and Remove Exhaustion may remove that rage, further testing is needed.