I have become kind of obsessed with Color, Killer, and Lust as a trio...
Like, not even necessarily the ship, just them.
Color has a type when it comes to his besties, they gotta be specifically cat coded, have their soul tampered with against their will (with Killer by the player and with Lust by their government. Btw, Underlust doesn't get enough credit for how horrifying of a concept it is. Imagine growing up knowing that, as soon as you become of age, you will be injected with a soul trait that doesn't belong to you and that will inevitably change you forever. Imagine being told that it's 'for the greater good' because your whole species is going extinct. The level of propaganda and lack of bodily autonomy those guys are subjected to should be acknowledged), and have lived in highly abusive environments for the big majority of their lives.
Everyone keeps wondering why such a seemingly normal guy is so determined to keep spending time with what they see as sex crazed freaks. No part of that belief is correct.
Color's type also extends to all of his besties being aroace. With Lust, that's a very unfortunate predicament, and Killer probably is unlabeled more than anything because he refuses to do any introspection lest he actually learns who he is and comes to hate it even more. But really, they are very aroace.
Whether this trio is platonic or not, they frequently go on dates to Ccino's cafe because they do love cats. And they go on nature hikes together. And shopping. And maybe they don't all share each others' hobbies, but seeing the other two happy and safe, and passionate about something is all the motivation they need to go along anyway.