Technically, I still haven't finished the grid. There are still quite a number of empty nodes, but other than that, it's all been done.
For me it was Rikku. Because I like Rikku for Rikku, I had her in my main team along with Yuna and Auron.
Very far into the game, just a step away from the final boss, I went to the monster arena and realized that I had to train Rikku, Tidus and Wakka in order for me to kill that one dragon (forgot its name) to obtain the Wings of Discovery. So because Rikku had already been power-trained, she was the one who managed to somewhat complete the grid.
So there. Your turn.
For me it was Rikku. Because I like Rikku for Rikku, I had her in my main team along with Yuna and Auron.
Very far into the game, just a step away from the final boss, I went to the monster arena and realized that I had to train Rikku, Tidus and Wakka in order for me to kill that one dragon (forgot its name) to obtain the Wings of Discovery. So because Rikku had already been power-trained, she was the one who managed to somewhat complete the grid.
So there. Your turn.