Chappu

Chappu was Wakka's younger brother in Final Fantasy X.

About Chappu
Because he chose to fight using machina in stead of the sword Wakka had given him, Wakka came to resent the Al Bhed on a personal level, in stead of just a religious one. Chappu and Lulu had a relationship together for some time before the events of Final Fantasy X. Luzzu, a crusader, was a good friend of Chappu and was the one who convinced Chappu to enlist in the Crusaders. When Wakka and Lulu found out, the both hit him hard. Chappu said that when he was done fighting Sin, he would propose to Lulu.

Death
While not known much about his death, it is known that he died somewhere near Djose, due to the fact that his body was crushed and left on the shore there. He died fighting Sin to keep Lulu safe, using an Al Bhed Machina weapon, most likely a firearm.

Appearence
According to Wakka, Tidus looks a lot like Chappu, which is why he had such an easy time bonding with him. Lulu was initially annoyed by this, because of her intimate relationship with Chappu. An illusion of Chappu, created by pyreflies, can be seen on the Farplane appearing before Wakka and, later on, Lulu as well. If looked at closely, it can be noticed that Chappu looks very similar to Tidus, other than the haircut and hair color.

Final Fantasy X-2
In Final Fantasy X-2, Wakka remembers that as a kid, Chappu told him about a sphere that showed their parents and nervous about his future role as a father, he goes looking for it. After the Gullwings helped him, he found a sphere, but not the one he was looking for. In the Sphere, Chappu says there never was a sphere of their parents in the first place. Chappu also says to Wakka that Wakka had been trying too hard to be a parent figure, and he just needed Wakka to be his brother.