After his wife died, 33-year-old Ronald wandered the wasteland until settling in Girdershade. Living in close proximity to Sierra Petrovita has made him feel even worse about being alone. His thoughts of loneliness are not as wholesome as most would think. Basically he misses the physical side of relationships. Feeling these urges, he's made several advances upon Sierra, who is completely oblivious to his motivations, because she is absorbed in her pursuit of Nuka-Cola. Ronald mistakes Sierra's rejection as being spurned, and this has angered him a great deal. Fortunately, he doesn't want to physically force himself on her but wishes to "get even" with her in other ways.
According to Sierra, Ronald is a skilled fighter. She recalls one occasion where he killed two raiders at Girdershade and punched Lug Nut in the face.
Should your character have the Black Widow perk, you can convince him to fetch the Nuka-Cola Quantums for you with the promise of a threesome with yourself and Sierra. Excited, Ronald will run off to the distant Nuka-Cola plant and die. If you then ask Sierra if he's been bothering her, she'll say she hasn't seen him in a while, but she's sure he'll come back. If you are able to escort Ronald safely to the Nuka-Cola plant, then he will enter it, but remain standing just inside of the entrance.
If you simply kill Ronald yourself, the previous speech option will still come up in coversation with Sierra.
If you give the Nuka-Cola Quantums to Ronald for The Nuka-Cola Challenge, he will attempt to woo Sierra with all the subtlety of a sledgehammer, but she fails to notice his obvious innuendo-laced words and instead interprets his behavior as an imminent marriage proposal.
If you kill Sierra and talk to Ronald, and tell him she's dead, a variety of options will open up. Among these are admitting to killing her and lying that the Nuka-Cola Company had her assassinated.
If you kill Sierra and then speak with Ronald, you have the option of convincing him (with a Speech check) that it was at the hands of the Nuka-Cola Corporation. On success, he attributes this to the Nuka-Cola machine he got her, which possessed a warning label declaring that anyone caught tampering with the unit would answer to the Nuka-Cola Corporation.