Why 'Yellowstone's Kai Caster Doesn't Believe Beth Knows About Rip Murdering Rowdy (Exclusive)

The young cowboy's life came to a tragic end on Sunday's episode.

Spoiler alert! If you have not watched the seventh episode of Yellowstone season 5, proceed with caution.

The actor behind Yellowstone's Rowdy believes Rip is keeping a big secret from Beth. ET spoke to Kai Caster after his character's shocking murder on Sunday night's episode, and the actor revealed why he thinks Rip (Cole Hauser) has stayed quiet about his crime for years.

"I don't think [Beth] knows, just because I think that present-time Rip is so stoic and he's not much of a sharer," Caster told ET. "I think that, unless Beth specifically asked him, [Rip wouldn't tell her]. It would have to be when they were adults, he would've told her. I don't think if she even asked him back then what had happened, I don't think he would've told her."

Rip and Rowdy's romantic rivalry over Beth (Kelly Reilly) started when the sole Dutton daughter tried to make the former man jealous by going out with the latter. Afterwards, Beth embarrassed Rowdy by rejecting him in front of the other cowboys, before expressing sweet words to Rip.

That didn't deter Rowdy, though, as Sunday's episode showed him telling Rip, with whom he was spending an uncomfortable night outside, "I could be holding that girl's a** with both hands, but no, I'm sitting here in the sage brush with you." The statement led to a violent fight between the men, which Caster believes Rowdy was fully expecting.

"I definitely think he was trying to provoke Rip a bit. I think that after everything that happened the last time you'd seen Rowdy with Beth and everything, I think he was definitely embarrassed by what happened," Caster said. "And obviously Rowdy's not used to that. I think he definitely was trying to provoke Rip and just push his buttons a little bit and just be Rowdy. He's a bit of a snake. He was just trying to do his thing."

Things escalated when Rowdy pulled a knife, which Rip responded to by hitting Rowdy repeatedly over the head with a rock. When the extent of Rowdy's injuries became clear, Rip decided to help by going to get John (Josh Lucas), at which point Rowdy showed his true goodness, suggesting Rip blame the injuries on a horse, rather than confessing to the fight.

"I think that is a really nice moment to show that Rowdy is a human being and he's a person that has hills and valleys of emotions and different walls that are put up," Caster said. "I think at the end of the day, Rowdy has a good heart and he's probably [been] a misunderstood person throughout his whole life, so I think that this was a great moment to show that he did care for Rip. I think he did show that a little bit at the beginning, that he really did care about Rip and I think he was attempting to put him under his wing, but the relationship stuff got in the way a bit."

Rip ended up telling John the truth, though, just before the men returned to find Rowdy dead.

"In my opinion, if Rowdy had won that fight, I don't think he would've killed Rip. I think that, to Rowdy, this was more of a male dominance thing, because Rowdy's such a macho dude trying to protect his ego all the time and all that stuff. I think that to him, it was just a fight over a girl, essentially, and a fight over status within the ranch, essentially," Caster said. "I don't think [Rowdy] had the same skin in the game as Rip did when [Rowdy] disrespected Beth, who at the time [Rip] considers family."

As for the purpose of this dramatic flashback -- whether it was to explain Rip's present-day character or to set up that the murder may be coming back to haunt the now-ranch manager -- Caster told ET that he thinks "it could be a bit of both."

"The way I interpreted the character a bit was that, in a way, Rowdy was like some sort of Rip before Rip, and was the exact version of Rip that Rip has... tried exactly not to be," he said. "I think that defined it in a way where he has shown pure loyalty in present time, and all you can really see from Rip in present time is loyalty. I think that was the opposite of what Rowdy showed. I think that the only time Rowdy showed it was in his dying breath. I think Rip took that to heart. I just think that what I can say in terms of my best guess is that Rip learned a lot from Rowdy on what not to be."

While the murder likely came as a shock to viewers, Caster knew his character's fate from the beginning. 

"During cowboy camp," Caster said of creator Taylor Sheridan's pre-production cast event, "I got the chance to stay with Taylor at his house and we had a lot of talks about the character and he hadn't necessarily finished writing my stuff yet, but he gave me the rundown that basically there was a lot of different options of how it was going to happen, but the outcome was the same every time."

When he read the script for his death, Caster, who considers himself a "big time" fan of the series, "was just amazed" at "how it all came together." Even though Rowdy may not have been long for the Yellowstone world -- and is unlikely to return in future episodes, according to the actor -- Caster was delighted to land the role and jump right into cowboy life.

"Cowboy camp was amazing. It was in Texas and I just had to jump right into it. I was with the whole cast who have done it four years in a row, but this was my first time on a horse, so I had a lot to learn in a very short amount of time," he said. "The cast was so welcoming and there were so many people that just took me under their wing a bit and showed me different things that they were good at and gave me tips on how to do it better. Everybody's just so fun. We had tons of fun."

"We made it fun, but for me it was definitely super stressful, but it ended up being one of the best experiences I've ever been a part of," Caster continued. "... I've been auditioning for the show since season 1, and I had been cast in a role in season 2, I believe, but that didn't end up filming. I've been working towards this for a long time, so cowboy camp was that first moment of it all coming together after all that work. I was very happy with it."

Yellowstone airs Sundays at 8 p.m. ET/PT on Paramount Network.