Eriah and Mercer slowly crawled their way through the ruin, taking out draugr and avoiding traps as they went. More than once, the Dragonborn had a sneaking suspicion that Mercer was being low-key difficult on purpose because there were several blunders that nearly cost them. It was only through her expert hammer work in tandem with his own skills they made it as far as they did. Eriah couldn't imagine why because the delays were likely giving Karliah the chance to slip away. They reached a chamber and Eriah heard the thrum of a Word Wall. While Mercer stood back, the Dragonborn approached the Wall and took the Word into herself and filed away to ask Paarthurnax about later. She knew she found the first Word to a new Shout, something to do with weapons. After that, the two trackers found their way to a Nordic puzzle door. "Shit," Eriah cursed. She had figured there would be such a door here but while they were crawling through the ruins, they hadn't come across the corresponding dragon claw key. Mercer approached and had her stand back while he looked over their latest obstacle.
"Ah, it's one of the infamous Nordic puzzle doors. How quaint. Without the matching claw, they're normally impossible to open. And since I'm certain Karliah already did away with it, we're on our own. Fortunately, these doors have a weakness if you know how to exploit it. Quite simple, really," the Breton said, fiddling around. Eriah's jaw dropped as the door's rings spun and unlocked the mechanism that allowed the door itself to slid down into the floor. "Karliah's close. I'm certain of it. Now let's get moving," Mercer said, ignoring the dumbfounded look on his companion's face. Taking up his place behind her, the Dragonborn refocused and slowly passed through the door. Suddenly, she was hit in the shoulder by an arrow and she felt some sort of paralysis encase her body. She fell to the floor, her hammer clamoring from her hand and her vision went black. She wasn't out for long and she watched Mercer walk past her. Another figure approached. "Do you honestly think your arrow will reach me before my blade finds your heart?" he asked.
"Give me a reason to try," the figure, a woman, shot back. "You're a clever girl, Karliah. Buying Goldenglow Estate and funding Honningbrew Meadery was inspired," the Breton responded. "'To ensure an enemy's defeat, you must first undermine his allies.' It was the first lesson Gallus taught us." Karliah said. Eriah listened as the two had a back-and-forth and was coming to some very startling conclusions. She was brought out of her thoughts when Mercer drew his blades. "Enough of all this mindless banter! Come on, Karliah. It's time for you and Gallus to become reunited!" he declared. The Dragonborn watched as the Dunmer instead uncorked a bottle and drank the contents. She suddenly vanished from sight. "I'm no fool, Mercer. Crossing blades with you would be a death sentence. But I can promise the next time we meet, it will be your undoing," she swore. Things were silent. Mercer turned to see Eriah staring up at him, helpless on the ground.
"How interesting. It appears Gallus' history has repeated itself. Karliah has provided me with the means to be rid of you, and this ancient tomb becomes your final resting place. But do you know what intrigues me the most? The fact that this was all possible because of you. Farewell. I'll be certain to give Brynjolf your regards," he said, striding over. With even her Voice sealed because of the poison, Eriah could only watch in silent horror as he knelt down and withdrew his dagger. She mentally screamed in pain as he stabbed her. She quickly lost consciousness, her last thoughts on Ulfric and her regrets over swearing to never let him know her feelings.
Against all odds, Eriah felt herself coming back to the waking world. Her vision blurred, she felt the cold wind sting her face. She heard a fire snapping and a dark shape came into her line of sight. Reacting out of instinct, the Dragonborn quickly sat up. "Easy, easy. Don't get up so quickly. How are you feeling?" came a voice. Her eyes clearing, Eriah looked up to see a Dunmer woman with unusual violet eyes. It could only be Karliah and she looked concerned. "Hold on... you shot me!" the Nordic woman said. "No, I saved your life. My arrow was tipped with a unique paralytic poison. It slowed your heart and kept you from bleeding out. Had I intended to kill you, we wouldn't be having this conversation," Karliah said, sitting down next to Eriah to check her wounds.
The Dragonborn looked down to see that her arrow wound and the stab wound were bandaged and healed somewhat. Karliah did have a point and Mercer had shown his true colors by stabbing her and leaving her to die. "Why save me?" she asked. The Dunmer thief took a deep breath as she finished checking Eriah's wounds and shifting away. "My original intention was to use that arrow on Mercer, but I never had a clear shot. I made a split-second decision to get you out of the way and it prevented your death," she responded. The Dragonborn blinked for a moment before bowing her head. "Then I'm in your debt," she said. "More than you'll ever realize. The poison on that arrow took me a year to perfect; I only had enough for a single shot. All I had hoped was to capture Mercer alive," Karliah said, stoking the fire.
She explained everything. How Mercer was a Nightingale, that he was the one who murdered Gallus and smeared Karliah's name, and how she had been on the run from the Guild ever since. Eriah listened intently. Things were adding up as far from what she overheard in the Sanctum and what Karliah was saying now. "How will you prove it now?" she asked, looking at her companion. Karliah pulled out a journal. "My purpose in using Snow Veil Sanctum to ambush Mercer wasn't simply for irony's sake. Before both of you arrived, I recovered a journal from Gallus's remains. I suspect the information we need is written inside," she responded, handing it over. The Dragonborn opened it and was greeted by a script she had never seen before in her life. "What the?" she muttered, flipping through the pages.
"I have no means to translate the journal. Wait. Enthir... Gallus's friend at the College of Winterhold. Of course... He's the only outsider Gallus trusted with the knowledge of his Nightingale identity," Karliah said. She and Eriah looked at each other. "Look, I know you don't have any real reason to trust me but I need your help. I need you to take this to Winterhold and find Enthir. He should be able to figure out what language this is in or point you in the direction of someone who might know," the Dunmer said. Eriah looked at the journal, weighing her options. On the one hand, getting this involved in Guild affairs was Brynjolf's fault because she nearly lost her life here but on the other, there was no way for the man to know it would turn out this way and Mercer had to pay for what he did. He murdered someone and nearly killed her, too, to protect his secret. She owed Karliah her life. She didn't have to save her but she did. With Mercer thinking she was dead, she was free to act against him more openly and help reveal the truth to the Guild.
"Can't you come with me to Winterhold?" Eriah asked. Karliah looked into the flames. "I'm afraid not. There are preparations to make and Gallus's remains to lay to rest. I promise to join you there as soon as I can," she said. "Okay. I understand," the Dragonborn said. She stood up carefully and tested her arm. Karliah had hit her in the left shoulder. While she wielded a two-handed weapon, her right hand still had the more important job of directing her strikes. Karliah had chosen her target well. Her stab wound twinged a little but it was bearable. It shouldn't interfere with her ability to fight. She whistled and, thank the Divines, Keizaal came when she called. It meant that most likely, Mercer never found where the horse hid so he couldn't either kill or steal her. "What is your name?" Karliah suddenly asked. The other woman smiled before turning to face her. "I'm Eriah Quintence," she responded. Karliah smiled back. "Thank you for helping me, Eriah. It means more than you know," she said honestly. "I'm the Dragonborn. Helping people is what I do. You didn't deserve what happened to you and now I have my own reasons for wanting to see Mercer's head on a pike. Don't worry, I'll find Enthir and we'll take Mercer down," she promised. She mounted Keizaal and was riding for Winterhold before Karliah could respond to the reveal of her identity as Dragonborn.
Karliah watched as her new ally drew farther away. Despite feeling abandoned by the Daedric Prince herself, Karliah felt that Nocturnal had sent the Dragonborn to help her. She couldn't imagine anyone else being that selfless. While on the run, Karliah had heard the rumors and it seemed they were all true. When the two reached the inner chamber, the thief had noticed that the woman with Mercer didn't appear to be one of the Guild. So she somehow got roped into everything and nearly lost her life in the process. In spite of that, Eriah was willing to help take Mercer down and for more than just personal reasons. It made her wonder if she was friends with some of the Guild. If that was the case, it would be easier for her to intercede on Karliah's behalf. The next stage of her plan involved returning to the Guild with Gallus's journal translated but it would amount to nothing if they didn't listen. If Eriah was on good terms with Brynjolf, it would provide Karliah herself with some added protection. For the first time in a quarter-century, Karliah finally felt hope.