In the spirit of headcanon, monkeytruth and everything that makes TES wonderous; where is your Nerevarine. Your Hero of Cyrodiil, your Agent and your Dragonborn? I'd imagine they completed the main quest, what else? Perhaps, more tantalizing, where are they now (4E 202 say) and how did they get there?
Agent - bosmer, dead and forgotten. He's caught in the Web.
Nerevarine -dunmer, until the Oblivion crisis he was the leader of a Boethiac cult that had peacebly annexed a large portion of the Sheogorad region, built Ald Redaynia up as a citadel of sorts. He catered to friends and fellow then-Anticipatory cultists, namely an exile Telvanni noblesse, part time Exalted Master and Night Mother. Didn't kill and was an apologist of Vivec and disappeared before Ald'ruhn was sacked. His post-disappearance destination or goals are unknown to me.
Champion of Cyrodiil - Imperial half-blood (part Mer, possible altmer) joined the Chantry of Akatosh. Died either in Greenheart or Alinor (island chain S. of Valenwood) Possibly assassinated.
Dragonborn - Breton, rules as imperial appointed Jarl of a newly created hold. Stormcloaks no longer a threat, she has become reclusive, training Thranes, this Era's Tongues. I imagine she seeks further conquest, looking toward the east and the Rift, seeking to ursurp its weak Jarl. She'd have plans to reclaim the Empire of Man, but would observe many paradoxes as the subjugation of Mer is not her desire (unlike previous Dragon Born emperors).