Prophet of Pity
From Halopedia, the Halo wiki
The Prophet of Pity is only known from a Halo 2 match held at E3. In it, players used premade accounts with the names of Halo characters. One team played as Spartans and used Marine names, the other team as Elites and using Prophet names including "Pity".
It is unknown whether or not he had been planned for Halo 2, but he never made it into the final game.