The Jed'ari Order was a merged order of Force-sensitive warriors that formerly served the Third Jedi Order or the New Sith Order. The order was created at the Treaty of Yavin IV. It was designed to help both sides fight their common foe: the Zungti.
The forming of the Order was met with protest by some in the Jedi Order. Rick Mallux formed the Jedi Traditionalists and refused to have anything to do with the Jed'ari.