It was late at night in Riften. Down in the Cistern, Mercer called Brynjolf over to his desk. "What is it, Mercer?" the redheaded Nord asked. "Thanks to your...associate, Eriah, discovering the buyer of Goldenglow and the funding party behind Honningbrew, I've decided I could use her help in taking out our enemy," the Breton replied. "Mercer...Eriah's done enough for the Guild and she's made it perfectly clear to me that she hated doing what she did to help us. Despite my role in all this, she's an outsider. Why have her help you kill Karliah?" Brynjolf inquired. "Despite her misgivings on our ways, even I admit that the woman has skill. However, it's because she's an outsider that she's the best person for this job. Why risk anyone else in the Guild when the outsider is expendable?" the Guildmaster said. Brynjolf scowled and leaned over the desk. "Eriah isn't expendable, Mercer. She's the only one standing between us and the dragons. Can't rob anyone if the cities are destroyed. Far as the Guild is concerned, she's more than earned her place among us, even if our way of life isn't for her. I won't let you speak of her that way," he said. The man wasn't afraid to stand up to his Guildmaster and given his position, was able to do so without repercussions. The whole point of the second-in-command was to keep the footpads in line and keep the Guildmaster honest.
Mercer gave him a dry look. "Look, Brynjolf, don't forget you're not innocent in her involvement either. You were so desperate to see an end to our troubles that you took advantage of her. You're responsible for her getting her hands dirty in the first place and then you appealed to her 'kind' and 'caring' nature just so you could keep her. If I didn't know any better, I'd say it was less about the Guild and more about the fact she was a pretty face you were bewitched by that motivated you to rope her into our mess. You're one of the best we have, Brynjolf, but don't pretend you actually care about her. Not that I give a damn about the girl but you're in no position to judge me in deciding that Eriah is the best person to accompany me to take down Karliah. Sure, dragons are bad for business but she remains as expendable as anyone. So go get her and bring her to me. The sooner we kill Karliah, the sooner we can put this behind us. If Eriah lives, she lives. If not...that's on you because you dragged her into this on your own," he said.
Brynjolf turned on his heel, feeling the burn of anger. Mercer had it all wrong. He did care about Eriah, in his own way. Sure, at first, he wanted a fling but as she worked with him to uncover the issues surrounding the Guild, he genuinely began to see her as a valuable friend. He protected her from the shadows by reminding everyone that she was doing good work in getting the Guild back on its feet, despite her personal morals, and she did befriend a couple of them. Mainly Etienne, because she saved his life from the Thalmor and Rune, because she went out of her way to help him figure out his past (though to no avail). Her relationship with Brynjolf himself was still standoffish but not like it had been initially. She was more open to joking around with him but still kept him at a distance. Thanks to some snooping around he did, Brynjolf understood her better than she knew. He couldn't fathom why Mercer would want to trust this mission with an outsider instead of one of the Guild. But nothing he could do. He went over to where Eriah was sleeping in the Cistern, which she had taken to doing the further into Guild affairs she fell.
Eriah felt her shoulder being gently shaken and sighed before opening her eyes and looking over her shoulder. "Brynjolf? What is it?" she asked, slowly sitting up and rubbing the sleep from her eyes. "Sorry, lass, but Mercer wants to see you," the man said. The Dragonborn swung her legs over the side of the bed and grabbed her hammer. She followed the master thief over to Mercer. "There you are. Do you remember the discussion we had when you brought back information from Gulum-Ei?" he asked. Eriah nodded. After being sent to Solitude to track down their Argonian contact in the East Empire Company, Eriah was aware that an errant Dunmer thief named Karliah was behind Goldenglow and Honningbrew, thus making her responsible for the Guild's problems. She was the one behind the previous Guildmaster, Gallus's murder. "During that discussion, I was too busy thinking about the implications of her return that I neglected to ask if Gulum-Ei knew where she was," Mercer said.
"Gulum-Ei told me she said, "Where the end began," the Dragonborn responded. Mercer leaned forward and she resisted stepping back. She hid it well but she never liked the Breton. Something about him seemed shady but he hadn't given her any real reason to distrust him aside from that. He wasn't fond of her either since she was an outsider and because Brynjolf went out of his way to watch her back. "There's only one place that could be. The place where she murdered Gallus... a ruin called Snow Veil Sanctum. We have to go out there before she disappears again," he said. "We?" Eriah asked. "Yes, I'm going with you and together we're going to kill her. Here's your payment for Solitude. Prepare yourself and meet me at the ruins as soon as you can. We can't let her slip through our fingers," Mercer said. He walked away before she could respond. Looking at Brynjolf, Eriah just slipped the coin pouch she had been given into a pocket. "Of all the people here, why is Mercer taking me?" she asked. The Nord man just shrugged.
"Best guess is that he finds your skills invaluable and better suited to the task, lass. Either way, even if you're not in the Guild, there's no crossing Mercer. Much like Maven, you're better off just obeying. If Mercer says he wants you on this job, then you just do it. I know this wasn't in our deal, Eriah, but even you have to admit you're in too deep now. You're just going to have to see this through to the end. If you succeed, then I'll make sure Mercer lets you walk away free after this. I promise," he responded. The Dragonborn looked a bit unsure. In the beginning, she wouldn't have thought his word was worth anything but over time, she realized that Brynjolf really was a man of his word. He'd become a valuable ally, even if his flirtation was annoying at times. The man started to walk away but Eriah caught his wrist, making him look back. "Thank you. For everything. I mean it," she said. With a charming smile, Brynjolf turned back to her. He caught her off-guard when he wrapped an arm around her waist, pulling her to him. "Thank me with a kiss, lass," he said, smarmily. It had the intended effect of making her scowl a little. "You're so shameless," she deadpanned, pushing him away. "Worth a try. I'd get going if I were you. Mercer isn't known for patience," Brynjolf said, in all seriousness. Eriah nodded before heading to the secret entrance out of the Cistern.
Once outside, she left through the gate and approached her horse, Keizaal. The piebald horse snorted as Eriah started tacking her for the trip. She looked at her map and located Snow Veil Sanctum. It wasn't too far from Winterhold. She'd reach it in about a week. She planned to stop in Windhelm on the way there to check on the state of the war. Ulfric hadn't summoned her in some time and rumor had it that the Imperials weren't giving any quarter for the Stormcloaks to advance. So currently, Ulfric and Galmar were biding their time and weighing their options.
About a week later, Eriah pulled Keizaal up to a camp outside the ruin. There was a dead horse there and she could see Mercer waiting for her. The Dragonborn dismounted and whispered in Keizaal's ear. The horse nickered before walking off. Eriah had decided to send her off out of potential harm's way. She would find a place to hide and wait for her mistress to whistle, something the Dragonborn had trained her extensively on. Mercer didn't need to know that, though. She approached the Breton who cocked an eyebrow at her. "Good, you're finally here. I've scouted the ruins and I'm certain Karliah is still inside," the man said. "You saw her?" Eriah asked, crossing her arms. "No, I found her horse. Don't worry, I've taken care of it... she won't be using it to escape. Let's get moving, I want to catch her inside while she's distracted. Take the lead," Mercer ordered.
"Understood," the Dragonborn said, remembering what Brynjolf said. "Just make sure you keep your eyes open. Karliah is as sharp as a blade. The last thing I need is you blundering into a trap and warning her that we're here," Mercer warned. Eriah privately rolled her eyes. Snow Veil Sanctum was a Nordic ruin and she had plenty of experience delving into them. She wasn't an idiot and she wasn't a klutz. But on the other hand, Mercer never gave her much credit and probably still wouldn't even if she did join the Guild. He found her an irritation at best but never went out of his way to make life hell for her either. The two went down into the pit where the door was and saw it was locked down tight.
Eriah stood back as the Guildmaster went to inspect it. "They say these ancient Nordic burial mounds are sometimes impenetrable. This one doesn't look too difficult. Quite simple really, I don't know what the fuss is about these locks. All it takes is a bit of know-how and a lot of skill. That should do it. After you," he said, after fiddling with the door and the locks disengaging. The woman pulled her hammer out and the two entered the ruin.