The Sphere Grid, Defined Final Fantasy X has done away with the RPG standard of "leveling up", and replaced it with a gigantic virtual board filled with incrimental stat increases, and battle ...

Talk to the girl and she'll teach Tidus how to use the Sphere Grid. Talk to the guy on the left to get Potion (x3) . Next, head to the right side of the upper deck to get the Al Bhed Primer Vol. I.

His Sphere Grid is designed in a way to easily branch into every other section. His role in battle is as the Blue Mage of the party, learning enemy abilities and sending them back at his opponents.