Originally Posted by
Talraen
Because it was in FFXI. Not by design, mind you, at least not at first. But FFXI Ninja has an ability that lets them automatically dodge a certain number of attacks, and combined with getting as much evasion as possible and a few other factors, it made tanking with Ninja not only viable but optimal for a large portion of the game's existence. In related news, Warrior was originally designed to be a tank in FFXI, but they gave up on that entirely after a while. For most of the game's heyday there were two tank jobs (Paladin being the other) and neither was a starting class. Because FFXI is weird.