Aang.
It's... relatively easy to deal with Sin. He's just a shell/armor, and not invincible at that (FFX party straight up breaks the things wings and punches a hole through it's forehead practically). Past that, you jump in and kill the Final Aeon and then Yu Yevon has nowhere to go and gets taken down easy enough.
When it comes down to it, Aang's able to fly about and is generally too small for Sin to hit short of trying to body slam him or AoE, and if he goes for that, Aang's got his tons of defenses and can simply blast his way into Sin, which if you're dealing with something as large as Sin, punching your way in is generally a safer bet for killing it unless you're literally able to nuke the whole thing at once.
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I have no idea who you are, but I thank you for arousing me. - Beruga
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