AHEGHM.. Cariku...... I imagine they were childhood friends for like. A year before Riku decided to dip and start anew on some other island. VERY young, Riku was 9 and Caribou 7.. edit: changed mind theyre the same age now just 3 months apart (for context Caribou is 32 now) Riku's taken in by Caribou & Coribou's grandma since he's assumed to be an orphan (tho as in every iteration of his backstory he'd actually just ran away) . otherwise there's not too much that happens in that yr time frame aside from unimportant details ive thought out- They meet again fuckihn!! 25 yrs later on Sabaody Archipelago ! Riku establishes that she's basically immune to Caribou's power lol (half haki use , half just being used to wading in swamps) 23 yrs later, while the whole impel down & marineford arc r going on, at an inconsequential Navy base where Riku happened to be kept at and joins the crew afterwards :) (partly bcz Riku convinces Caribou that "having an oni crewmate will raise [their] image!! Blackbeard'd be so impressed!!") Riku initially plans to go off on his own after being freed but is convinced otherwise (insert scene ive been thinking abt for weeks now but cant sit to write down)

anyway see him badly hiding in a barrel

Their actual relationship is a little one sided ? Where Caribou does genuinely enjoy the attention and romantic interest, but is a little annoyed at how forthcoming Riku is.. tho she does remind him a little of times when he was more so a simple town miscreant rather than a straight up villain u_u Theyre def a little codepentent (i cant help.it) Cari just cant/wont do pda while Riku will cling onto him 90% of the time lol