Eridan in each quadrant!
Pale-
Feferi: Eridan makes it clear he dislikes the pale quadrant, as he refers to it as a shithole in their dialogue together, and explicitly states that the only reason he got into it was so he could push it to the next level. This is a very clear analogue to dating someone just so you can get your dick wet, as their dialogue is written in a way that Feferi says “well, I like you but not in THAT way.”
Pale is still a type of romance even if it is called “brotherly” love but it is specifically a sexless romance, where any remotely sexual activity is frowned upon, and largely at most you “shoosh pap” someone. Pale is one of the many ways Homestuck makes it very clear that quadrants Do Suck Actually and it is the only one Eridan actively hates.
Black-
Vriska: Eridan was in a caliginous relationship with Vriska, which he thought was more serious than it wound up being. She only seemed to date him because of their ancestry, and dropped him for Tavros when that looked more beneficial to her goals. He genuinely was super into her and I am convinced that he lost his virginity to her. There’s no way he didn’t, I mean… we all read that journal from Mindfang come on.
Vriska is a case of just she liked him enough to be in a sexual relationship erm I mean “reproductive quadrant,” so he took it, and he got very committed to the bit, which we see in his design- a cape which calls back to Dualscar, blue in his pants and scarf. He also tries the destiny thing with her, but when he sees it isn’t working anymore, he too drops it for something better.
Destiny comes up again as a theme with Feferi, who we will get to AGAIN in the red quadrant. With Vriska, Eridan got to live up to his ideal of a tale of romantic intrigue, as he recreated this ideal every day with her, and was using her so he could live up to his other ideals, namely genocide, which HE DID INTEND TO COMMIT. Eridan USES PEOPLE, he sees them all as means to an end, and sometimes that end means getting his dick wet or having someone to talk to. Eridan only loves people for the purposes they serve to him, which can include being his friend. He will turn on someone very quickly if he sees they can’t do that for him anymore, or even pose a threat to him and his plans. We see this all in his relationship to Vriska.
Rose: Eridan’s hate for Rose comes from his desire to prove his belief system right and hers. He sees a potential rivalry with her and again, uses her as a means to an end in his search for something he can defeat Sollux with. Note that he is fixated on getting between Sollux and Feferi even on the meteor (“bigger ships to sink” means Feferi and Sollux) and he lost his duel with Sollux while still weilding Ahab’s Crosshairs.
Sollux has exceptionally powerful psiionics and Eridan views himself as powerless and impotent (uesless shitty wands). He likes magic because it is powerful, and admires Rose for wielding it, but sees it as a far off and impossible ideal. Kanaya makes him a wand powered by Science and he sees himself with that power he yearned for. He wants to use this more powerful thing (his belief) to defeat Rose and rise above everyone else who gave him any shit EVER. Him blowing up Jade’s Johnnytop is an explicit call back to Rose blowing up his computer and is a very blatant threat to both her and Rose, and really anyone else who intends to “disrespect” him.
In his dialogue with Rose he also mentions wanting to introduce her to his culture, and makes it clear with Jade how disgusting he finds human anatomy or familial relations, indicating a general disdain for the HUMAN aspects of Rose. He shows respect for what he assumes is noble lineage from her, and tries to make it look like things are even between him and her, but points out nagging little flaws like her interest in magic or human romance that he wants to fix. tldr; Eridan likes Rose because he is a school shooter analogue who fetishes goth women.
So, Eridan’s caliginous romances seem to be strongly based on his ideals/beliefs, which makes sense given his classpect as a destroyer of/through belief. Blackrom is basically his form of power fantasies more or less, a bit analogous to a boy fantasizing about being with a variety of beautiful women he can have sex with all day long, much like the content existing in his books albeit with the limit of being more quadrant based.
Red-
Feferi: these are the only EXPLICIT red feelings we see from Eridan in the comic. The main reason is obviously because she is a fellow seadweller and they refer to themselves as “fated moirails.” This concept is explained here, just prior to their introduction. Eridan, as I mentioned before, only dates her to get his dick wet, which is obviously going to be in part out of desire to purify the bloodline, with hers being the purest yet, but also out of genuine love, which he discussed with Karkat, who knows Eridan’s affection for her is true. As Erisolsprite, this is also made to be very clear.
Jade: Jade mentions Eridan hitting on her, he denies this but is probably lying and mentions “flushed desperations.” This is obviously because he was desperate, and he later changes these to what might be ashen given his interest in her “rivalry with the other female.”
Nepeta: Eridan’s flirtations with Nepeta are presumed to be flush. Nepeta remarks how they were insincere and creepy (twice: once with Equius and once with Jasprose.) and while she doesn’t outright despise or resent him, she does think he is a little weird and makes her uncomfortable. Eridan calls her the “kitty cat shipper cave girl” in his talk with Karkat and regards her with obvious disdain, which indicates that neither side really likes the other. Eridan was just doing it because he was desperate, and seems to have seen her as a potential red match.
Notice the pattern with the three “red matches.” All 3 are cutesy, high energy girls with very childish behavior and interests. Weird 🤔surely this means nothing.
Karkat: Karkat is most likely a flushed interest given Eridan’s fondness for him. In their last dialogue together in the comic, Karkat notes how Eridan was probably flirting with him when they were still on remotely good terms. Of course, Eridan’s attitude towards him has soured when we reach Kanaya: Return to the Core, as he takes Karkat’s “neglect” of him due to not visiting him on his planet, very personally. He talks to Karkat immediately before his killing spree as a bit of a manipulative “what I’m about to do is your fault, try me bitch.” That’s the subtext of their dialogue in return to the core pretty much. He also calls Karkat an assblood behind his back. He might be nice to him but only because they can talk romance and have a close bond, sharing secrets in such. He’s still racist and still dehumanizes him, and it can be assumed that as a couple, Eridan would basically turn Karkat into his sex slave. I’m ngl but a lot of Erikar ship art (including the “wholesome” stuff) kind of does this, even when it incorrectly places Karkat as the dom/top.
Red romances seem to be Feferi/surrogates for her and emotional/sexual need fulfillment with Karkat. He hates being “just friends” with anyone and feels the need to advance it due to both idealism and strongly implied sexual urges. There are two innuendos with Eridan, one in his final dialogue with Karkat and one with Kanaya. Read how she teases him and tell me he doesn’t want to fuck Feferi I dare you.
Unknown-
Cronus: a “romance” we see a non canon Eridan accept out of desperation for anyone to fuck or be involved with. Speaks for itself. Could be either caliginous or flushed, the comic never says. Eridan probably wouldn’t care either way, as his motivation for getting with him is the same as Nepeta, minus the Feferiesque appeal, and he speaks to and about him with a great deal of disdain, with an alternate version of him even cheering when a different Cronus is called out for his creepiness by Vriska.
Equius: Equius never specifies what type of advances Eridan made on him. What we know is Equius is a submissive sexual personality obsessed with the caste system and Eridan is a dominant sexual personality obsessed with the caste system. I think he wanted something red and to turn Equius into his lackey/fuck toy. This is appropriate given the symbolism of one of them being a prince and the other being a horsey.
Ashen-
Sollux: Eridan only seems invested in Sollux for ashen reasons. Feferi suspects him of trying to pull her and Sollux out of their quadrant through their duel on Brains and Fire, and it’s clarified in his dialogue with Terezi of all people that he is indeed interested in something ashen with Sollux:
This likely could be motivated in part by wanting to ruin what Sollux has with Feferi and also possibly impressing Vriska as he mentions very spitefully and dramatically wanting a better blackrom than what he had with her. Sollux is just a surrogate, someone caught in the middle of Eridan’s bullshit, and not someone Eridan genuinely pines for. He’s using him, more or less, and wants to kiss/fuck him in front of someone more than kissing him alone.
Terezi: We get little info on his relationship to Terezi besides that she dislikes him a great deal, but it can be assumed he is aware of her relationship to Vriska. Familiarity between him and her can be seen in that he calls her by not only name but a nickname! It is VERY possible he flirted with her ashenly as a means to get both her and Sollux involved with him and put Feferi and Vriska’s eyes on all three of them.
Kanaya: Eridan asks Kanaya to get ashen with him to spice up his relationship to Vriska and get them closer. It’s a very similar motivation to why he does this with Sollux and Terezi. It can therefore be assumed that Feferi was right when she said he intended to pull her and Sollux out of their quadrant, as this is exactly the same thought pattern at play with Kanaya.
Jade- very minor. He assumes that she and Rose have a rivalry and wants to give her an edge in it with his gun. Given his already pretty voyeuristic use of the ashen quadrant and flirtations with both girls, I wouldn’t put it past him to have had ashen feelings for her and Rose. It also would be a means to get closer to the both of them, but after she enrages him with her rejection this is not going to happen and he nukes her computer. Jade also mentions Eridan projecting his own tendencies onto her and Rose, which is why he thinks they have a rivalry to begin with, and I think that she actually is correct in her assertion here. Reread all of my analysis here and tell me this guy DOESN’T project onto others, I dare you!
So yeah, he basically uses the ashen quadrant to spice things up when things aren’t good enough for him anymore, and get people closer to him. Again, he objectifies and projects onto people and uses them as a means to an end, which once again is VERY in line with his status as a hope player.
