Liberum or Antigravity, is a Legacy which renders the laws of gravity non-applicable for the user. The Garde with this legacy can run up walls and across ceilings.
Nine first discovers this legacy during his final training session in the Lectern. When cornered by Sandor's drones, Nine turns to use the wall to backflip over the drones. However, he finds that he can stand on the vertical wall. He then runs away and uses his Legacy to explore Chicago by walking up skyscrapers.
This Legacy is later seen in the Mogadorian mountain base in a battle to escape. Nine runs along the wall and ceiling to pass over a group of Mogadorians and land behind them where he proceeds to kill them with his bare hands. Nine uses this Legacy again, tied with his Legacy Transference power to allow Four to run with him on the underside of a bridge to avoid running into more Mogadorians.
Nine also transfers his Legacy to Marina in order to win a capture the flag game in training.
Those with the title of Pittacus Lore are able to replicate this legacy with the use of Ximic.