Armpit polycule, minus tamama, for obvious reasons. Dororo and Giroro caught feelings for each other first, kululu had feelings for all three, keroro had feelings for Dororo growing up but internalized homophobia made him act out and be shitty to him. Eventually the others helped keroro come out as queer, and in turn, confess to dororo. It was very tough at first for them, due to the many broken promises and hurtful actions and words over the years. Giroro and keroro realized they had feelings for each other soon after. Kululu took the longest to join the polycule, due to his fear of opening up to people, he's not a feelings guy. Dororo actually helped him come out of his shell a bit over time, kululu trusts him above anyone else the most. Keroro and kululu are chaos when together. They all smoke weed together while tamama is at Momoka's.
Thank you for coming to my ted talk.