5. Lucia vs. Zophar - Lunar 2
This is probably the darkest theme on the list. It takes about a minute and a half in before it even starts to sound like a battle theme. Still, I like how the song starts off peaceful, then it gets dark, and then it gets epic. A pretty cool transition.
My Top 25 RPG Final Boss Themes #2- Lunar Eternal Blue - YouTube
4. You're Not Alone - FFIX
Of all the FF battle themes, this one stands out as my favorite. Technically, it's not a pure battle theme. I'd still count it though, since it does play during a few battles.
Final Fantasy IX OST - You're Not Alone! - YouTube
3. Sinistral Battle - Lufia 2: Rise of the Sinistrals
This is probably the most epic battle theme of all time. It perfectly captures the feel of evil villains dueling legendary heroes.
Lufia 2: Sinistral battle theme - YouTube
2. Flight - Xenogears
One word describes this song perfectly: heroic.
Xenogears OST - Flight - YouTube
1. I'll Face Myself - Persona 4
This is my current favorite. It's just amazing, although admittedly not as epic as some of the others. Still, I really like the way this song is played. It gets you in the mood to kick some serious ass.
Persona 4 OST- I'll Face Myself - Boss Battle- - YouTube