Here's my shot at Karkat x Terezi. Don't blame me if it's not the best ^^;
Your name is KARKAT VANTAS. You are currently residing on the meteor with the remaining trolls that are alive and a few of the humans.
And by a few, you mean two: Rose Lalonde and that pesky Dave Strider. God has he been on your nerves lately. It's like he hasn't annoyed you enough, being the smart-ass he is, but he's also been sneaking off with Terezi. You can't even imagine what they could possibly be doing. Just thinking about it makes you angrier than usual. Why do you even care? Usually you wouldn't give two fucks about someone's relationships, unless they're actually going to you for advice. Actually, not even two. The amount of fucks you give are so low, that not even Troll Einstein can try to THINK of that number. But for some reason, not this time. Just thinking of Dave doing anything with Terezi pisses you off. You would've probably done something about it by now, but you don't know where they sneak off to. You don't even know where to begin looking, especially on this vast meteor.
You happen to see Rose walking by, and decide to see if you can get any information out of her. "Rose. Where does your friend usually wander off to at this time?" you ask. Rose blinks. "If you mean Dave, I'm not quite sure. But I have seen him go through those set of stairs quite often." She points at a set of stairs that you've never really noticed before. You immediately head down the stairs without saying anything else. Why didn't you ever just ask the Rose human before? This is easier than you imagined.
You see a door with light shining out of it in the distance. You head that way and look inside. The walls are completely colored with chalk, and ... are those cans? "Look who decided to show up", a male voice chuckled. You spot Dave Strider piling up cans as if they were towers. Terezi is sitting right there next to him. "Karkles, you finally decided to join the party!" she chuckles. "Sorry if you came here to meet the mayor", Dave says, "He's over there sleeping. But that's okay, the mayor of Can Town needs his sleep too". "I didn't come all the way here to see a fucking mayor of some fake city", you exclaim. "I need to talk to Terezi". "Well, go on and say it, man." Dave replies. "Privately", you finish. You glare at him as Terezi walks out of the room. You follow her and close the door so Dave can't hear.
"What is it now?" Terezi asks, clearly confused. "Okay, let me let you know here that I don't give a fuck about you 'hanging out' with the Strider human, but you have been missing too many important conversations about future topics. I can't let you miss anything else, so I suggest you back the hell off the town building and actually do something fucking productive?" You know most of this isn't true, but you can't let her know that you actually detest her growing relationship with Dave. Terezi frowns. "Is that what this is about? It just sounds like jealousy to me!" she says with a grin. You laugh sarcastically. "Jealousy? It's anything but jealousy! You're just missing out on important plans on the game!" "I can smell liars, you know. And there is definitely a liar here, and it's not me!" Terezi smirks. "I am not lying!" you reply,"You're just trying to change the subject!" Terezi gasps. "I am not lying! A judge never lies! Maybe I AM doing things with the cool kid behind your back! Who knows? You're never there to see anyway!" Hearing this coming from Terezi infuriates you. "Don't fucking joke around like that! You know what? Just stay the fuck away from him, okay?" And with that, you flee the scene.
You rush into the room you sleep in on this awful meteor. Why are you so pissed off? Ugh, maybe you're a little jealous of him. Okay, a lot jealous. That doesn't mean you have to tell her that, though. Who even cares about your feelings? You certainly don't. Even if you are jealous, why jealous of HIM? Oh right, because he has Terezi. Maybe ... maybe you're flushing for her. No, that can't be true. ...Is it? You decide to brush it off and just get some decent sleep.
You wake up by the sound of Rose and Kanaya's loud talking. You hear them babbling nonsense that no one even cares about. You sit up and walk outside of your room. Both of them become quiet once you walk in. You stare at them. "What?" you finally ask. Kanaya speaks up first,"Have you and Terezi been fighting?" "What? No", you reply. "Are you sure? We could hear you from up here", explained Rose. "Any argument Terezi and I may or may not have had is none of your fucking business", you snap. "She also told me to tell you to 'meet her in Can Town', though I'm not quite sure what that is", remembered Kanaya. "Is Dave going to be there?" you blurted. Kanaya shrugs.
You decide to go there anyway. Maybe you can get rid of this weird feeling you've been having. Even though you try to deny it, you are pretty sure this feeling is in the red quadrant. Since when have you been feeling this towards her? Maybe if you get it off your chest, it'll go away. But, then she'll make fun of you for it. But the feeling won't stop.. You decide to just 'spill the beans'. Of course you mean that in a metaphorical sense, because who the fuck knows what a bean is, and why would they purposely spill it? Must be a human thing. Oh well, you've learned to be culturally sensitive by now.
Surprisingly, you don't see Strider in Can Town, only Terezi. "Hey", you call, trying to get her attention. She looks up at you. "Oh, I didn't see you walk in!" There was a silence. "Sorry about what I said yesterday. I didn't think that would actually offend a tough troll like you!" Terezi exclaimed. "No, it's fine. I was just overreacting.. Wait, tough?" you reply. Did she really call you that? Terezi chuckled. "Yes, tough! Usually Karkat the leader is tough about this kind of thing!" "Well, I guess I can't fucking help myself, can I?" Terezi chuckles. "Nope!" You both laugh.
"So... Terezi", you stutter. "I'm the one who should apologize. I was completely overreacting about some obviously fucking pointless thing. I'm pretty sure I acted that way because, I think I actually was pretty jealous of you and Strider." "I knew it!" Terezi remarked. "Let me fucking finish." you reminded her. "I also think I may have some ...", you hesitate. Just say it! It's too late to stop now! "...red feelings for you." Oh god, you actually said it. You can already feel the red coming to your cheeks. Terezi giggles. Why is she giggling? "You think I didn't know that, nubby? How blind do you think I am? Oh wait.." she says, cackling more at her own joke than at the actual situation. "But, I actually have some red feelings for you too." ...What did she say? You certainly didn't see that one coming. Now you REALLY feel the red coming to your cheeks. You hide your face in embarrassment, but Terezi immediately pulls your hands off you face. "Don't do that, I like the smell of your cherry red blush!" she exclaims. You can't even find the right words to say at this point. "Shut the fuck up, Terezi.. " you say embarrassingly. Did she really say she had feelings for you too? You can't even take up all of this information at once. It just seems too unreal.
Now that you think about it... "If you have feelings for me, then what about Strider?" you ask. Terezi looks confused. "What about him? We are just friends who help the mayor out in Can Town! You thought we were matesprits?" You feel like a fucking asshole at this point. "Yeah, it kind of seemed like you were. But not anymore, I guess." Terezi smiles. "Good! Because I was just going to ask someone else if they would like to be my matesprit!" Your cheeks start to feel red again, but you're becoming a little less embarrassed at this point. "And that 'someone else' says, What kind of fucking idiot would say no to this question?" Terezi smiles and says, "I'll take that as a yes!"
"Oh, it's getting late. I have to get some rest! See you later, Karkles!" Terezi says, then gives you a kiss on the cheek. "See you later", you reply. Terezi was just about to leave the room, when Dave walks in. "Yo TZ, you busy? Can Town still needs cleaning. Looks like a fucking tornado blew up in here." Terezi nods at you and says, "I think I'll pass this time. I have some more... important things to do." She chuckles. "Hey that's fine, I can wake up the mayor and get him to help me," he replies. And with that, they both walk out of the room.
Wow, what a long day. You sigh. The arguments between you and Terezi are over, AND you get her as a matesprit? You lay back and think, "When did you get so fucking lucky?"