There is a side quest available which sends the Dragonborn to talk to Thonar Silver-Blood. Rhiada will greet them, and one can persuade her to let them talk to Thonar. The first dialogue that they pick with him (any of the 3) sets off the 2 undercover NPCs, who will kill Rhiada unless the Dragonborn stops them in time. However, take care to not hurt her or Thonar when in combat against Nana Ildene and Donnel, or guards will appear and the Dragonborn may receive a bounty.
Rhiada is married to Eltrys. If the Dragonborn starts "The Forsworn Conspiracy" quest and talks to Eltrys, they will find out that she is pregnant. However, there is no script of this in the game, as Rhiada does not appear to be pregnant or ever have the baby in the game. If she lives through the attack, Thonar will flirt with her, asking about her relationship status.
"I'm just a servant. Don't pay me any mind."
- Who's in charge here? "You want Thonar Silver-Blood. He handles all the family business. If you're here to talk politics, though, you'd want his brother Thongvor. He spends most of his time in Understone Keep."
- I want to know about the Silver-Bloods. "It's an old family. Very well-respected throughout the Reach. The Silver-Bloods run nearly all the lands in this Hold, as well as the local inn. And of course, they own Cidhna Mine, the finest prison and source of silver in Skyrim."
- What kind of patrons do you have? "For one, the landowners of the Reach. It goes without saying that they rely heavily on us for our silver and support. All the miners, farmers, and laborers in the Reach get their daily wages through us. Nepos the Nose handles that part of our business. He has a way with the workers."
"What? Oh. Bye."
Asking to see Thonar Silver-Blood:
"The Treasury House is really just for patrons of the Silver-Blood family. You don't belong here."
"I'm sorry. We're only interested in helping our patrons."
- I need to see Thonar. "I'm afraid he's asked to not be disturbed. He has important business."
- He's expecting me. (Persuade)
- "Oh, I'm sorry to keep you. Head right in." (passed)
- "No. He isn't." (failed)
- Business, you say? (Bribe)
- "Riches are a gate-opener around here. Head right in." (passed)
- "Private business, I mean. No visitors." (failed)
- I wasn't asking. (Intimidate)
- "Go... go right ahead then. Don't let me keep you." (passed)
- "I must have misheard you. Did you say you were leaving?" (failed)
- I'll try later, then.
- "I doubt he'll be free, but all right."
- He's expecting me. (Persuade)
Betrid: "Rhiada, did you clean the tables today? They're filthy!"
Rhiada: "I'm sorry, Betrid. I'll clean them right away."
Betrid: "No, don't bother. You're useless, as always. I'll get Ildene to do it."
Rhiada: "I'm sorry, Betrid. I thought I had cleaned the tables properly."
Betrid: "Oh, stop apologizing. It makes you look like an idiot. Learn to talk back a bit, girl! Why, when I was in the temple...."
Rhiada: "The temple, Betrid? You were one of Dibella's faithful?"
Betrid: "I misspoke. Never mind what I said. Now get back to work."
Rhiada: "You have worked here in the Treasury House for a long time, haven't you Ildene?"
Ildene: "Yes, child. Nana Ildene has taken care of the Silver-Bloods for many years...."
Rhiada: "It's just... aren't you worried about the Forsworn? Maybe it's not safe here."
Ildene: "Don't you worry Rhiada. If any Forsworn coming knocking on our door, Nana will let you know...."
Rhiada: "Thanks Nana. I feel better now."
Thonar: "You're a very pretty young woman, Rhiada."
Rhiada: "Why, thank you Thonar. I'm flattered."
Thonar: "You're married, yes? To that young metal worker?"
Rhiada: "Eltrys, yes, just last season we were wed."
Thonar: "He's a lucky man to have such a beautiful young wife."
Rhiada: "Thank you, Thonar. That's generous of you to say."
- "I'm just a servant. Don't pay me any mind."
- "Working in the Treasury House isn't so bad. I earn good money."
- "Ildene has been working in the Treasury House since before I was born." ―If Nana Ildene is alive.
- "I have records I need to tend to."
- She is one of the only characters who owns and wears Tavern Clothes.