I've decided to do something different with the poll system. Instead of doing a repeat if a similar question of which game you like best, or which boss is the coolest, I've decided to a "versus" system.
This means that I'll set up a poll every week with a character from the Final Fantasy universe to face off against another character from the Final Fantasy universe. I'll try to keep it as balanced as possible, however, there are characters that are overpowered for whatever reason.

Anyhow, this week is Ninja vs Ninja.
I just watched Ninja Assassin with my girlfriend and thought I'd do this.
You the community most vote on which Ninja is the strongest to truly decide.

What is the strongest and most interesting final boss in a Final Fantasy in your opinion? When explaining who, also explain why.
You can explain based on:
-Difficulty
-Unique abilities and features
-Bio, such as how he became powerful
-etc...

This poll kind of follows RajaHibiki poll about FF6 characters, although this is about main characters of the Final Fantasy games.