Modryn Oreyn is the Champion of the Fighters Guild in Cyrodiil. He can be found in his home in the city of Chorrol. He is a rather sharp speaker, quick to irritate and anger, but fiercely loyal to the Fighters Guild, and proud of the members that show skill and competence. He has little tolerance for members who would tarnish its reputation, or those he deems as a threat to the Guild, whether it is a single member or an entire chapter, as one worth looking over carefully.
Oreyn's part in the Fighters Guild questline begins with a mission: a wizard named Argoth arranges for the retrieval of an artifact from a warrior named Azani Blackheart. The mission goes awry, with only five of the twenty men returning. In the escape, Vitellus Donton, one of the Fighters Guild head Vilena Donton's two sons, is slain, trying to defend the group as they flee.
Oreyn tries to investigate the matter, discovering later that the Blackwood Company managed to complete the mission. He finds this hard to believe, as he is unconvinced of any particular skill on the part of the Blackwood Company, and surmises that something is amiss.
He keeps a vigil over Vilena's remaining son, Viranus Donton, providing the young warrior with obscure contracts to keep the boy sharp, skilled and confident, while keeping it secret from his mother, at one point pairing him up with the Hero. At the same time, Oreyn finds that the Blackwood Company seems to be taking over many jobs, leaving some Fighters Guild members to lounge while waiting for some form of money, and even losing members, who favour the growing business of Blackwood.
When it becomes too suspicious, and apparent that the Hero is a little more than just skilled, he investigates further into the Blackwood Company. The wizard Argoth turns up dead, and the artifact missing, leading Oreyn to believe that the mission may well have been a setup. To expose Blackwood as frauds, he and the Hero go to find and slay Azani Blackheart, who is rumoured to be holed up at the Ayleid ruins of Arpenia. Upon arrival, there is no sign of anyone, save for a few rats and mudcrabs, confirming Oreyn's suspicions that Blackheart and Blackwood struck a deal, with the latter weaving a story at the expense of the Fighters Guild to build their reputation, while Blackheart keeps his artifact and simultaneously thins the ranks of the Guild. After slaying Blackheart with the Hero's aid, he returns to the Fighter's Guild.
Later, Oreyn sends Viranus on yet another contract, with a group of guild members, but loses contact with them. The Hero reveals that all of them died, though it is apparent that the Blackwood Company is responsible. Oreyn is expelled from the guild due to Viranus' death, but remains loyal, conducting investigations on Blackwood on his own in order to bring them down.
Once the Hero manages to reclaim their rank, Oreyn speaks with them. When the Hero manages to capture Ajum-Kajin, one of the Blackwood's leaders, and interrogate him the two find that Blackwood is over 100 men strong, and that its leader is Ri'Zakar, but Ajum kills himself with an enchanted ring before he can reveal the secret behind Blackwood's strength.
As a result, Oreyn sends the Hero to infiltrate Blackwood. He later finds the Hero unconscious in Leyawiin. The Hero informs Oreyn that Hist Sap, a powerful narcotic, is being produced and is responsible for the berserker-like characteristic of the Blackwood Company fighters. As a dangerous side effect, the hist sap causes delusions, which explains the Blackwood Company's indiscriminate killing. After the Hist Tree is destroyed, Vilena Donton steps down as Guildmaster, and Oreyn becomes assistant to the Hero, who takes Vilena's place.
When asked to become the Guild's second in command, Oreyn at first appears hesitant, and says that he is getting into retirement and that his art is becoming quite good. The Hero can look behind Oreyn to see his picture depicting the interrogation of Ajum Kajin, which looks like it was painted by a very small child. However, after a few moments thought, he reconsiders, sarcastically (though perhaps good-naturedly) remarking that the guild might well fall around the Hero's ears without Oreyn to keep them in line. After this, Oreyn becomes second-in-command, carrying out the Hero's orders and managing the guild in their absence.
- In Malacath's quest in Morrowind, the Nerevarine was tasked with killing the last members of the Oreyn family. Malacath believed the family was dead, but Modryn Oreyn is a descendant of this family, meaning Malacath was wrong.