The Twelve Olympians was a group of twelve lead researchers worked for Olympus Corporation - the former O corp in District 15.
Their main goal was to maintain and exploit the Everlasting Flame, which was O corp’s Singularity, while inventing more technological devices. The Singularity was utilized to generate energy while consuming almost no Enkephalin, as well as other unknown uses according to Hestia.
After the Flame was “stolen”, O corp lost the patent war and became a collasped Wing. The Twelve Olympians then joined another Wing, with Hestia’s position being replaced by Dionysus.
The Twelve Olympians was established by Cronus in O corp, with each member being chosen by him and his siblings. The leader position was assigned to Hestia initially, which was then passed down to Zeus after her departure.