Pardon me chiming in, but i'd like to emphasize the incredibly ambigious nature of tiers. There's no actual unanimous classification, with everybody having their own interpretation of what these mean, depending on the community they hail from. For example, to me, low-tier and unpowered are two entierly different things, low-tier defined as a power level within which a human melee combatant is still capable to compete, even at a disadvantage, as opposed to having no chance of winning at all.

The above, of course, is strictly my opinion and defenitions. What of that applies to the tournament itself will probably be clear once the rules and regulations for character sheets will be announced.

Ah, and just in case Rilla's explanation doesn't fully satisfy: mentioned above, character sheets aim to provide the concrete limitations and capabilities of the character, as well as explain the way their abilities function. Said information, combined with combat posts, which provide detail on the exact circumstances the combatants are in and the actions they perform - such as their positioning, stance, any momentum resulting from actions, the speed and trajectory of their motions and ect. - is exactly what allows you to not only to announce yourself victor in a fight, but prove the legitimacy of such a claim and have it be firmly grounded.