In the show they are best friends as they are always teaming up like in Big Time Songwriters in which James said that Carlos always takes Kendall's side. Also it has been seen that Kendall has helped Carlos multiple times in the show and it shows that they cared for each other.
In real life they are also close best friends and shown to be more like brothers. Carlos and Kendall are opposites when it comes to being clean as Carlos is organized while Kendall is not, but Carlos has said that he keeps Kendall's area clean and organized and Kendall said that Carlos is always there for him. Kenlos the pairing of Kendall and Carlos is the counterpart of Jagan the pairing of James and Logan.
Carlos follows Kendall's plan to trick Kelly so she won't know the set isn't being done in the studio but instead just play around with the power tools and bang on wood with a hammer.
In the Let's stay in our PJs (All Christmas Long) feat. Snoop Dogg video Carlos and Kendall are shown more together in the video and the same goes with James and Logan.
It also revealed that Carlos always takes Kendall's side.
Kendall and Carlos wear Viking hats made of aluminum foil (which James refers to as foil helmets) and hair extensions to attack James and Logan's fort. (Jagan)
Kendall tells James and Logan to save the dogs while he saves "The Carlos".
Kendall tries to show Carlos how a real/great relationship is. Kendall even makes Jo do the thing she hates just to help Carlos know about a good relationship.
Kendall try to save Carlos from Jennifer's "spell"
Kendall tries to make Carlos break up with Jennifer. Kendall even pretended to broke up with Jo to show Carlos how easy it can be.
Kendall gives Carlos a "lip balm" that makes his mouth no feel anything. Making Carlos break up with Jennifer.
Kendall agreed to make another Cameo on a show after seeing Carlos' puppy face.
Kendall gave Carlos a 'plan' so Carlos can make a move on Dara Laramie, though Kendall was kidding, Carlos took it seriously. In the end, Kendall voluntarily assisted Carlos.
Kendall stood up for Carlos against Dara's stepmother after she told Carlos to stay away from Dara.
Kendall tried to apologize for Carlos accidentally whacking a lady.
He (along with Logan) stopped Carlos from breaking out.
They partnered up against Griffin in the game show.
They argued over who spins the wheel better.
Kenlos Moments (Real life)
Their Point of View about Organization- Carlos: ''''Having Fun in Life.....Organization is FUN" & Kendall: "Life's too Short to be Organized".
In an Interview with Jojo Wright, Jojo asked: "Is that your...what is that?" Kendall said:"I don't know what that is, oh this, I was like Are you pointing at Carlos, That's MY Carlos".
Love for Animals: Carlos had said if he wasn't working on Big Time Rush, he would be studying to become a Marine Biologist/ animal trainer and be working in Sea World. Kendall has said that he would be working on becoming a biologist or/and animal trainer if it wasn't for BTR.
In some Interviews, Carlos and Kendall hit each other playfully.
Of all the boys, Kendall and Carlos are seen to share their clothes the most.
Kendall Messing around with Carlos in a Popstar interview: Ideal summer dates
Carlos Well, I like the amazing weather in California this Summer, so I just got a jeep that has no top so I think, you know, driving down the PCH Kendall through the PCH? Carlos and you know, just driving down- Kendall Can I go on a date with you? that sounds awesome! Carlos *looks at camera* Wow
Carlos has revealed that the producer told them that they (James Carlos Logan & Curt) have to be close friends but they didn't felt chemistry (friendship) with Curt. So they ended up replacing him with Kendall which Carlos said is like his new brother.
In a behind-the-scenes video Kendall shows concern for Carlos when Logan took revenge (Carlos recorded Logan sleeping) on Carlos by pushing him out of the stage into the floor.
In If I Ruled The World and Elevate, Carlos and Kendall have their own combination moves while James and Logan have their own. They seeing to team up in some songs as two groups (Carlos and Kendall James and Logan).
Before singing Windows Down Carlos and Kendall team up against James and Logan by dividing the audience into two sides to see which side screams "Woo Hoo!" the loudest.
Brain Surge Interview:
Kendall He’s a bench warmer. (Carlos realizes what Kendall just said and punches him) Carlos I’m not a bench warmer! Kendall (pushing/slapping Carlos’ back): Ahahaha. I’m just - I’m just messin with ya.
Kendall and Carlos are the only band members with tattoos. Kendall has 4 two on his back and one on each his arms, and Carlos has one on his right side of the body.
Carlos and Kendall are the first two to join Instagram.
They sit next to each other in some interviews and performances.
Sometimes they whisper and talk to each other during interviews and performances.
Both Kendall and Carlos, have said that their favorite One Direction's guy is Niall.
When Carlos and Samantha Droke broke up Kendall was there to support Carlos through his break up.
In an interview, Kendall said he didn't have any sister so Carlos joke with him saying that they were sisters.
Carlos I'm his real sister. Kendall *sassy voice* Yeah he's my sista. Carlos What? No I'm his sister. Kendall He's my sista. Carlos: Sista. *snap* Kendall: Sista. *snap*
Carlos is the only other member of the band that has been seen wearing a Choose 180 necklace.
Kendall wants to learn Spanish because he believes Carlos insults him. With Carlos only replaying that it's only love.
Kendall I want to learn Spanish because I think Carlos insults me a lot. Logan It's true, he does. Carlos NO. It's all love, guys. All love.
When Carlos gave his opinion on Justin Bieber's Beauty And A Beat ft. Nicki Minaj video by saying it was similar to their Windows Down video a lot of "Believers" insulted and started hating on Carlos. Kendall tweeted/ tried to defend Carlos by calling them silly cyberbullies and to stop hating.
Carlos and Kendall have created "Big Time Flight". Which is that every time they sit together on a plane they do a Tweet/Photo Spree.
Kendall believes Carlos will be a great director and gives him credit for it. Kendall also said that Carlos knows much more that he gives himself credit for.
Kendall and Carlos are the two band members that give more hints about their songs episodes and albums then James and Logan.