Since you have allready been told that ESO is too early for Jiub, I just want to add that Jiub didn't make Cliff Racers extinct. He drove them off Vvardenfell but there are still plenty on mainland Morrowind. (Might be less after the read year though).
Cliff Racers.... the most annoying thing i have ever had to fight in a video game. Those were the morrowind days walk 2 feet and fight a cliff racer... forever... seriously. If you've ever played morrowind chances are you killed more of those things then you have anything else. The second you kill one another one takes its place.... I hope they stay extinct... stupid annoying squawks.
Uhmm ESO takes place in the Second Era. Arena(not sure) Daggerfall, Morrowind in the Third Era Oblivion Starts in the 3rd and becomes the 4th when the Main Quest is concluded. Skyrim is 200 years after Oblivion. Jiub or St Jiub or That-ugly-dude-who-wakes-the-Nerevarine-at-the-start-of-Morrowind dies at the Siege of Kvatch by then he wiped the Cliff Racers of Vvardenfell. Mjoll went hunting them with her father 200 years later probably on the mainland of Morrowind. But i do hope that those sneaky flying vermin return in a new installment since i love to hate them..