0

Memory Beta, the wiki for licensed Star Trek content.

0 was a malevolent entity from another dimension. Approximately two million years ago, a young Q encountered 0 after an encounter with the Guardian of Forever, and the two cosmic beings became traveling companions.

With Q's assistance, 0 used the Guardian of Forever to bring into the Universe the beings known as Gorgan, The One, and (*), and the group committed many atrocities, including the destruction of the T'Kon Empire.

The Q Continuum eventually banished 0 beyond the galactic barrier, where he remained for half a million years.

In 2374, 0 manipulated Professor Lem Faal and the crew of the USS Enterprise-E into breaking through the galactic barrier, but was defeated once more by the combined efforts of Q and the Calamarain. (TNG novels: Q-Space, Q-Zone, Q-Strike)