He has gruff and impatient mannerisms. He tends to keep to himself when he is not at his stall in the market.
The Dragonborn first meets him when first arriving to the city, when Weylin is seen attacking Margret. Weylin is seen speaking to Hogni before then drawing his dagger to make his move on Margret unless intercepted before he performs his murder of her. He will comment on how close he was to the murder.
During the Daedric quest "The Taste of Death," it is revealed that he, along with a few other citizens of Markarth, is a cannibal. He implies that he sells human flesh at his shop if talked to at the feast in The Taste of Death, however this may just be a macabre joke as human flesh can never be bought from his stall, even by a cannibal.
"Did you see that madman? A Forsworn agent. Here in the city."
- Who was he? Who are the Forsworn? "Think he worked down at the smelter. Lot of the laborers there are sympathetic to the Forsworn. They promise people they'll kill off all the Nords that rule over the Reach. Nothing but murderers and saboteurs."
- I was actually looking to buy something. "Didn't you just see that woman getting attacked in front of us? We're closed."
"This has ruined my entire day."
- The Taste of Death
"Now this is going to be a good feast."
- Wait. I know you. ""The bloodiest beef in the Reach!" Ha ha ha."
Back at Markarth:
"Don't try to haggle with me. Buy or leave."
- You were at Namira's feast, weren't you? "Don't go talking about that. Only the dinner guests can know."
Degaine: "Alms. Give me some meat, you fat Nord!"
Hogni Red-Arm: "What did you say to me, Reachman?"
Degaine: "I said give me some meat. I'm hungry, and the Divines know you don't need more food in that huge gut of yours."
Hogni: "You little twig. I'll snap you in two!"
Degaine: "Just try it. Maybe a little time inside Cidhna Mine will get rid of all that fat on you."
Hogni: "Look at you, begging on the streets. Learn a trade."
Degaine: "Picking on me again, you backbiting Nord? Tired of those prissy nobles turning down your rotten slabs of venison?"
Hogni: "How dare you. No one turns down cut meat from Hogni Red-Arm!"
Degaine: "Hogni Red-Arm, more like Hogni Fat-Arm."
Hogni: "You there, pretty lady. You need some fresh meat for your family? Just look at the blood coming from this cut...."
Hroki: "That's disgusting, get that rotting carcass away from me!"
Hogni: "What's wrong? You have to look at the blood closely to see the quality of the meat. How else will you know it's fresh?"
Hroki: "I don't need to know if it's fresh from this distance."
Hroki: "Ugh. You're the most disgusting merchant I have ever seen. The guards should take you away."
Hogni: "The only people I offend are cheats who don't pay me enough gold coin, or idiots who don't know good meat when I throw it at their faces."
Hroki: "If you ever think of throwing meat at me, I will have you dragged off to Cidhna Mine so fast the guards will yank those filthy arms of yours off."
Hogni: "What do I do to deserve such hatred? You give people good food and good prices, and all they do is insult you."
- Good meal
Eola: "Thank you for coming to dinner, Hogni."
Hogni: "I never miss a good meal."
Hogni: "The toes are my favorite part. I hope I get to take a few home with me."
Lisbet: "I always preferred the liver myself. My brother had such a juicy liver."
Hogni: "When was your first meal, Banning?"
Banning: "Do dogs count?"
Hogni: "Of course they don't count!"
Banning: "My friend Marex. We were hunting, and I thought he was an elk."
Hogni: "That must have been quite a surprise."
Banning: "Either way, I came back with meat for the table."
- "Hey you. Yeah, you. Fresh meat for your stomach."
- "The bloodiest beef in the Reach."
- "You want a cut of venison or mutton? Of course you do."
- "Don't try to haggle with me. Buy or leave."
- "A man like me makes a lot of enemies. People are always trying to cheat me."
- "I paid extra for the biggest room in the Silver-Blood Inn. I need space to stretch these arms."
- "Who? You mean that woman who was attacked in the market the other day? Don't know her. Guards dragged that Forsworn's body away, though. Last we'll hear of that."
- "Don't go talking about that. Only the dinner guests can know."
- "The Forsworn. Here inside the city." —During "The Forsworn Conspiracy," when Weylin is attacked
- "Can't believe anyone was dumb enough to mistake you for a Forsworn agent." —After completing "No One Escapes Cidhna Mine" by siding with Thonar Silver-Blood
- "Huh. Heard you broke out of Cidhna Mine with those Forsworn. Do you have any idea how many died?" —After completing "No One Escapes Cidhna Mine" by siding with Madanach
- "Namira spoke to you? I knew this feast was going to be something."
- "Stormcloaks or Imperials. Either way, all they want is everything for free and you to lick their boots."
- If he and the other Namira cannibals are killed, he will be the only merchant who receives no replacement at his stall.
- While he offers mutton in his patter at his stand, he never has any. (It would have to be imported from Cyrodiil as there are no known, if any, sheep in Skyrim.)