Paine?
Ding ding ding.
1) I would absolutely, most definitely, never have a theme song. Ever. Seriously. - Yuna and Rikku, sure, but Paine'd just want to kick their ass.
2) But... if I did (ironically, you understand; even if I do have a theme song, it's not like it fits my character to have one)? It'd... probably be a Thomas Lehrer song. Who can turn a can...? - Reference to Silent E, of which Paine has two (Pan->Pain->Paine)
3) Off the subject of theme songs, somewhat, I'm hardly the most famous of my team; that title'd definitely belong to our esteemed leader. - High Summoner and Sin-slayer Yuna.
4) My leader also shares something in common with Elvis. - Impersonators!
5) However, in battle? I'm the one who brings the pain. - True, Paine does bring herself into battle. With her legs. >_>
Your field, Shale.