I'm looking for an animated sci-fi series from the early 2000s. It involved an evil military organisation of some kind and the protagonist was trying to sabotage them or was a double agent or something similar. I remember they all wore the same kind of mask/uniform and you didn't really know who was underneath the masks. I also remember their "base" looked like Mayan pyramids.
Another detail that may be just in dubbed version was that the organisation had a salute and they shouted something like "We are Brothers Tanner" (this might not be fully accurate since it's a translation of a dub).
It had a really distinctive look, somewhere between anime and western animation, but I remember that it was all dark colours (blacks and reds). The main bad guy also wore a mask and a dark red cloak/robe.
In talking to a friend who also remembers seeing it, we think it might have been French or German.