I'm not completely decided between these two as my first...
There existed a group of vampire hunters on a plane unknown on Nirn. The group had no official name, but they were sometimes called "Clan Deathbane", after a title that had been awarded to three of its members. After the group's leader, a monk-turned-priest named Jerem Deathbane, was slain by Ash, a particularly powerful vampire-mage they were hunting, the surviving members vowed revenge against the vampire at all costs. They pursued their prey across that world. With nowhere left to run, and realizing he could not defeat all of them, Ash travelled across the planes to escape. It took several months, but the hunters were able to track Ash's destination to Cyrodiil on Nirn. They opened a gate and went through.
Ash had lain a trap for them. Immediately on arriving on Nirn, they were cursed with weakness and sluggishness. In addition, they were unable to use the form of magic that existed on this plane. The priests and mages of Nirn could not remove this curse, having no knowledge of their physiology, nor of Ash's form of magic. They would have to regain their power the hard way.
With no trace of Ash, and not having the power to face him even if they did find him, the group decided they should seperate and blend in until the time was right...
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Name: Markalus Aldred
Age: 27
Sex: Male
Race: Appears to be Breton
Hair/Eyes: Light Brown / Blue
Class: Wizard (Might something like Athletics instead of Alchemy or Conjuration)
Markalus could feel the magic of Nirn, but he could not yet manipulate it. He joined the Mages' Guild to train in it's use, and to search for records of other visitors from other planes. He found none. Could the Deathbanes possibly be the first to travel to Nirn? His homeworld had more than its fair share of extraplanar mages as visitors, but most of the people here scoffed at the notion. He would have to begin experimenting with travel magic.
Markalus's first attempt at a teleportation landed him in the bedchambers of a wealthy Duke's daughter.

He was quickly dragged to the local prison compound and tossed into the nearest cell...
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Name: Marakas Alderus
Age: 29
Sex: Male
Race: Appears to be Imperial
Hair/Eyes: Dark Brown / Blue
Class: (Custom - Paladin-like)
Marakas went straight to the Fighters' Guild and began training with a ferocity that frightened his masters. He would neither regain his strength, avenge his father and his fallen leader, nor return to his homeworld by taking it slow. He scowled at his comrades' plans. Study! Prayer! Searching! Marakas would grow in power until his prey learned of him, and draw Ash to HIM. It had worked before, it would work again.
When the time was right, he joined the Arena. This was the most direct way to draw someone's attention, after all. But after nearly a year, he still hadn't found any trace that Ash was paying attention to him. Enraged at the futility of it all, Marakas went berserk and nearly killed his opponent in what was supposed to be a warm-up match.

The Arena masters decided to toss him jail for a few days to cool him off...