|“||I'm gonna miss you, Preppy.||”|
|— Joaquin to Kevin before he leaves Riverdale.[src]|
The relationship between Kevin Keller and Joaquin DeSantos initially began as a heated hook up but eventually developed into a more complex and intense relationship. They began dating shortly after meeting, although, it was later revealed that Joaquin had only gotten involved with Kevin on the orders of FP Jones, as way for the Southside Serpents to keep tabs on Kevin's father, the Sheriff. Despite his orders, however, Joaquin developed real feelings for Kevin.
Kevin eventually learned of Joaquin's deception as well as his involvement in the cover-up of Jason Blossom's death, and the couple broke up when Joaquin left town.
While they both live in Riverdale, Joaquin resided on the south side of town, commonly associated with the Serpents, which explains why he and Kevin had never crossed paths before that night at the Twilight Drive-In.
At closing night of the Twilight Drive-In, which Kevin attended with Cheryl and Veronica, members of the Southside Serpents gang began being loud and disruptive, bothering the three. Kevin turned around to tell them to keep the noise down, only to be distracted by one of the members eyeing him intensely.
Later, as Kevin went to get a popcorn refill, he bumped into the same guy who had followed him. The two eventually started making out behind the drive-in and the mysterious guy introduced himself as Joaquin. Kevin decided to give him his phone number, only for Joaquin to notice that his last name was Keller, as in the Sheriff's son. The two then promised each other that they'd keep what was between them a secret, as Joaquin was a gang member and wouldn't want Sheriff Keller to find that out.
After Moose Mason was assaulted at Andrews Construction, Kevin asked Joaquin, who had become his boyfriend by that point, to get himself, Archie Andrews and Moose into a bar called the Whyte Wyrm, a local hangout for the Southside Serpents, whom Archie believed to be behind the attack. Joaquin did so, but warned them to play it cool. While Moose looked around the bar to see if he recognized anyone, Kevin and Joaquin played a game of pool, wherein Joaquin teased Kevin about keeping the money he'd won from him on the game. Archie then confronted one the Serpents, Mustang, which led to FP Jones to eject them from the bar.
Later that night at the Sunnyside Trailer Park, FP tossed Joaquin a duffel bag containing Jason Blossom's varsity jacket, which was last seen in Jason's getaway car the night it had been set on fire. He told Joaquin to hide it in a safe place as it was their insurance in case everything went to hell. He then checked in on Joaquin's progress with Kevin, as they were going to need that inside line with Sheriff Keller. Apparently, their relationship was only a means to an end, however, Joaquin began to feel guilty as Kevin had developed genuine feelings for him. FP chuckled, and told him that they all had a part to play. 
Despite the fact that Jughead's 16th Birthday Party was supposed to be inner-circle only, Kevin invited Joaquin to the party, who he claimed was inner-circle because they were dating. During the party, unbeknownst to neither Kevin nor Veronica, Joaquin eavesdropped on their private conversation pertaining to her father's trial and his potential involvement in Jason Blossom's Death. Shortly afterwards, he small and quiet event quickly escalated into a full blown house party as the party was crashed by Cheryl Blossom and Chuck Clayton, along with many of their classmates.
Joaquin and Kevin did not allow this to put an end to their good time, and proceeded to make out in the kitchen, until they were interrupted by FP, who asked Joaquin to show him to the bathroom, which was merely an excuse for them to talk privately and Joaquin informed FP of what he had overheard earlier. He was then ordered to find out what the Sheriff knew, through Kevin. Downstairs, Joaquin and a riveted Kevin watched as a devious gamed of "Secrets & Sins", took place, however, the game quickly turned violent between Jughead and Chuck Clayton, which resulted in FP bringing an end to the party.
Kevin invited Joaquin to attend Riverdale High School's Homecoming dance as his date where they slow danced together. Kevin admitted that it was the first time he had brought a boyfriend to a school event, in fact, it was the first time he'd had a real boyfriend, usually he just had hookups. They were interrupted by Jughead and Kevin then noticed his father at the dance and went over to see what was going on. As he walked away, Joaquin left and walked the other direction, watching with a worried look on his face.
Kevin later interrogates Joaquin over what he knows when it's discovered FP called him the night of his arrest for Jason's murder. Despite Joaquin's hesitation, Kevin presses him for information as "the Sheriff's son" and Joaquin reveals his ties to Jason and FP. Joaquin then decides to leave town, as Kevin states that he felt fooled by him as he had no idea who he was now. However, Kevin decides to give Joaquin one last kiss, while Joaquin smiles and states he'll miss him as he boards the bus to San Junipero.
- Despite Kevin stating he would keep the relationship a secret, by Chapter Eight, their relationship had become somewhat common knowledge and the two went together to homecoming and prom.
- It's implied that Joaquin never intended to fall for Kevin but did regardless.
- Joaquin: "Pay up."
- Kevin: "I'm going to get this back, right?"
- Joaquin: "You wish, preppy."
- ―Kevin and Joaquin play pool, Kevin loses.[src]
- Kevin: "Do you ever go down to Sweetwater River?"
- Joaquin: "For what? Fooling around?"
- Kevin: " [nods] "
- Joaquin: "Do you?"
- Kevin: " [smiles] I've been once or twice."
- ―Kevin and Joaquin at Jughead's party[src]
- ↑ Grassi, Michael (writer) & Piznarski, Mark (director) (February 16, 2017). "Chapter Four: The Last Picture Show". Riverdale. Season 1. Episode 4. The CW.
- ↑ Cohen, Julia (writer) & Katzenberg, David (director) (March 30, 2017). "Chapter Eight: The Outsiders". Riverdale. Season 1. Episode 8. The CW.
- ↑ Lundin, Britta & Paterson, E. Brian (writers) & Wilkinson, Dawn (director) (April 13, 2017). "Chapter Ten: The Lost Weekend". Riverdale. Season 1. Episode 10. The CW.
- ↑ Aguirre-Sacasa, Robert (writer) & Sullivan, Kevin (director) (April 27, 2017). "Chapter Eleven: To Riverdale and Back Again". Riverdale. Season 1. Episode 11. The CW.