Titan Biology Research Society

The Titan Biology Research Society, also known simply as the Titan Society (Kyojin Gakkai), is a Marleyan scholarly organization established sometime after the Great Titan War to investigate the Eldian people and the true nature of Titan power. Its findings are shared with the Marleyan military, while the Eldian population confined to the internment zones appears to be told nothing; whether ordinary Marleyan citizens receive the information is likewise unknown.

Tom Ksaver, a onetime bearer of the Beast Titan, works among its researchers, driven by the question of what Ymir Fritz came into contact with 2,000 years earlier when the power first appeared.

Theory is the Society's first contribution. Before the year 832 its scholars propose that every Titan and every Subject of Ymir is linked by invisible "paths" that ignore physical space, all converging on a single point they call the Coordinate, which is the Founding Titan itself. The Society also investigates why Zeke Yeager can command Titans spawned from his spinal fluid, though the question is never resolved; the researchers have no idea that royal blood inherited from his mother grants his Beast Titan abilities resembling the Founder's own. Its scientists further note that memories transfer more readily between Titan inheritors who share family ties. Even so, Eren Yeager remarks that Marley's scholars understand very little about the Titans, and that Zeke knows more than any of them.

Weapons development is its second contribution. Every serum of Titan spinal fluid produced in Marley traces back to the Society, giving the authorities the means to transform Eldian criminals and traitors into mindless Titans, whether abandoned to roam the wilds of Paradis Island or hurled against enemy armies in Marley's imperial wars. The formula is refined so that the size of the resulting Titan can be set by whichever Marleyan officer administers it, and the serum also serves to pass the Nine Titans from one Warrior to the next. Zeke's fluid opens darker possibilities: in 844 hundreds of dosed Eldians smuggled into an enemy capital are transformed at once, a tactic cheap enough that Marley repeats it, and gas weapons laced with the same fluid later turn the entire Paradis village of Ragako into Titans.

Tom Ksaver is the Society's only named affiliate, a scholar fascinated by the legend of Ymir Fritz and the unseen paths binding her descendants. He carries the Beast Titan for a time and passes both the power and his obsessive curiosity to his protégé, Zeke Yeager.