High Rimmer was a version of Arnold Rimmer created by the Triplicator.
He had all of his negative aspects removed and was a serene and cheerful individual who had a half moon symbol on his forehead instead of an "H" like most holograms.
Like the rest of the high crew he wore a hooded white robe. He played the role of "Agony" in the play the highs presented to the original crew.
The original Rimmer was convinced that his high counterpart was a hippy and a loser. High Rimmer was killed when a remote-controlled Lister crushed his light-bee. He took his impending death and that of the High Lister with great composure. ("Demons & Angels")