Technique Ranking, Tech Rank or simply Rank, is a system used for classifying techniques by their power.
The classification goes from 5 (lower) to 0 (higher):
The lowest level, techniques that have low or no chance of killing.
May kill weak enemies.
May kill enemies at the user's level.
May kill very strong enemies.
May kill extremely strong enemies. Some might hurt and even kill gods.
Godly, may kill gods and sometimes destroy entire realms.