Nearly three thousand years ago, AR-N-O-Q was a Green Lantern that gave his ring to the alien TO-T-U-K on a distant world. As of this writing, nothing is known of AR-N-O-Q's service to the Corps.
TO-T-U-K would retire after the so-called Crisis on Infinite Earths. The Guardians of the Universe sent the retiring Green Lantern to the world of the Puffball Collective to pass the ring to the next Green Lantern.
[Tales of the Green Lantern Corps Annual #3]
AR-N-O-Q is memorialized in the Crypts of the Green Lantern Corps on Oa.
[Green Lantern/Sinestro Corps: Secret Files #1]