Its not a released runeword. A long time ago back in .07 I think it was (correct me if I'm wrong on the history) when the runeword combos and potential names were still available to the "hackers" (Im not a hacker I dont understand any of this really) I think someone cracked the game and found the list of words (you can find the list on Diabloii.net I think among other places). Since then the combos have been changed of many of the released runewords when they were finally activated but the actual names have remained the same. Theres a long long list of them...Oblivion was merely one of the still non-activated words.