You're a human, hybrid of a Shinigami, Hollow, Quincy and Fullbringer.
Within you is unlimited potential, you are able to become a War Factor, achieve what is seen as impossible and always come back up from the brink of defeat. You start with the power level of a 6th Seat Lieutenant Shinigami. You're capable of achieving the level of a Captain in a fraction of the time it would take for someone else and go much beyond when motivated enough.
Even if you are at the brink of death, if you were motivated enough, you would come back, and strong enough to defeat whatever was able to defeat you.
You could even substitute the Soul King himself if the conditions were right.