The promotion to Master requires you to complete three quests – “Information Gathering”, “Infiltration”, and “The Hist”.
Information Gathering – Talk to Modryn Oreyn in Chorrol and he will tell you that you need to kidnap Ajum-Kajin, a high-ranking member of the Blackwood Company, to determine the source of the Blackwood Company’s power. Travel to Glademist Cave, northeast of Chorrol, There will be a number of guards there, so kill them however you wish and then talk to Ajum-Kajin and he will follow you back to Chorrol. Take him to Modryn’s house and tell him to sit down. At this point, you’ll have to interrogate him by either raising his disposition above ninety or beating him up with your fists. Either way, you’ll be able to get him to answer two questions before he kills himself. Talk to Modryn afterwards to receive your reward.
Infiltration – Talk to Modryn Oreyn and he will instruct you to infiltrate the Blackwood Company to determine the source of their power. Talk to Jeetum-Ze at the Blackwood Company Hall in Leyawiin and convince him to let you join the Company. Once you’ve joined, he’ll give you some Hist Sap to drink and you’ll be transported to the village of Water’s Edge where you have to clear out the goblins that have invaded the town. Clear out all of the houses and you’ll be transported to Modryn’s house where he tells you that you were found unconscious on the street. He tells you to go back to Water’s Edge to find out what happened there. When you return to Water’s Edge, you’ll find that all of the “goblins” that you killed earlier were actually the townspeople. Talk to Marcel Amelion before returning to Modryn.
The Hist – Talk to Modryn once again and he will task you with destroying the Blackwood Company. Return to the Blackwood Company Hall in Leyawiin. When you enter, Ja’Fazir will call you a traitor and attack you, along with several other members of the Company. Once they’re all dead, search Ja’Fazir’s body for the key to Jeetum-Ze’s room on the second floor. Enter his room, kill him, and take the key to Ri’Zakar’s room off of his body. Go to Ri’Zakar’s room on the third floor and kill him as well. On his body, you’ll find the key to the basement. Return to the first floor and go down to the basement where you’ll find and kill two more members of the Company. Finally, you have to destroy the machine pumping the Hist Sap. Find the two pipes on the table near the furnace and add them to your inventory. Once you have them, find the pumps on either side of the tree and activate them with the pipes in your inventory, destroying each pump. When you leave the basement, you’ll be attacked by Maglir who you’ll have to kill before you can return to Modryn. Modryn will congratulate you and send you Vilena Donton who strips you of your rank of Champion, but the promotes you Master of the Fighters Guild.