How can you not know who thancred is?

Did you not watch any cutscenes or read any of the text up to this point? Or heck, even watch the ARR opening. You're even a black mage! Your entire level 1 to level 15 storyline focused on thancred and no one else! >_> (Assuming you started as a thaumaturge)

And even if you didn't start in ul'dah, you would have seen thancred many times. In every last waking sands cutscene nearly, and in the entire Ifrit plotline.

Seems like you just didn't pay attention, man.