The maximum possible chakra affinities (not considering chakra mixes) for any player besides me will be 3. Shinobi of The Hill can obtain a third nature if they inherit their village's legacy. However there is a very unlikely scenario where I can get killed and the body of my blood can be extracted and transfused to a player, allowing them to master all 5 chakra natures. If this were to happen, I see my blood being sold in the black market instead since it will most likely have an incredible value in the SLO world and will not be worth the advantages it provides.
But really, it's as Konohuro quoted Bruce Lee, having an affinity with all 5 chakra natures does not turn one into a legendary fighter.

The advantage of being free from natural weakness of natures against each other and the advantage of being able to make use of natural strength of natures against each other comes at the cost of having to master more jutsu. And mastering jutsu is easier said than done. Truly mastering a jutsu means both training your character's body to get used to and able to handle the jutsu and it also means knowing how to properly use the jutsu as a player. I am referring to the well-known saying:
Not the weapon but the hand.
Follow @SLO_MMORPG