Benjamin hatched in the Octarian domes into a relatively poor family. Since his mother wanted to have a daughter she could raise to be an Octoleet like herself, she didn't really care about him and left most of the child-raising duties for Benjamin to his father. The relationship between his mother and father only further fell apart after they had his younger sister Isabel and found out that she's deaf, and it completely crashed into divorce only weeks after his mother had to get a hysterectomy. Benjamin was ten at the time, and he and Isabel were left in their father's custody since their mother wanted nothing to do with them. His adoptive older brother Amphio came into his life when he was sixteen, as Amphio was in desperate need for stable housing after being on the run from his abusive home situation for a couple years and Benjamin's father needed help around the house and a bit of extra income coming in to better make ends meet. Amphio ended up moving in with Benjamin's family as a result, and he quickly became like an older brother to Benjamin and Isabel.

About a year later, he accidentally ended up meeting Jay while he was out on a mission as Agent 3, and they ended up becoming unlikely friends and later catching feelings for each other. This meeting ended up resulting in them getting dragged down to the Deepsea and Benjamin taking up the role of Agent 8, and after the events of Octo Expansion he returned to his family in the domes. A month after Octavio permitted him and his family to move up to the surface as thanks for his work as Agent 8, and once up there he got back in touch with Jay and the two officially started dating. The two were happily together for a year and a half or so, having even moved into an apartment together after they both graduated school, but after an Agent mission that nearly ended in disaster and a poorly-timed promotion from Cap'n Cuttlefish, Jay started to distance himself emotionally from the people he was close with so that way in the event that Agent work claimed his life it wouldn't hurt those he cared about so much. Benjamin wasn't letting Jay distance himself like this though, so Jay broke up with him. This breakup really hurt him, and he quit Agent work and moved back in with his family for a while until he ended up getting a lucky break in a modeling job.

Benjamin quickly rose into popularity after his lucky break, and he soon moved back out on his own again. At this point he tried to find another partner, but his breakup with Jay left him afraid to open up to others since he didn't want to get his hearts broken again, so he ended up continuously finding and leaving new partners in a cycle of loneliness and fear, leaving a trail of heartbreak behind him. As he grew in popularity from his career fewer people he met were actually interested in dating him for him and not just the status they got from dating a famous person, and his feelings of isolation just got worse. This changed when he met Taylor however, as Taylor was the first partner he'd had in a long time that was actually invested in their relationship and not in it for the social clout. Like his other previous relationships he quickly grew afraid that he'd just be inviting heartbreak again if he got too invested, but because of how bad his loneliness had gotten before he met Taylor he was finally able to push through his fear and admit it instead of just ending the relationship. Because of this, Benjamin was finally able to start healing from his breakup with Jay, and him and Taylor quickly grew close.

Several months pass, and Marina calls up Benjamin one day asking if he could help her out with testing a new project she's working on. Benjamin is hesitant at first, since though he is finally healing from his breakup with Jay he still doesn't wanna see him, and it's only after confirmation that Jay won't be involved that Benjamin agrees. From here, the events of Side Order are put into motion, and while he's assisting those that got pulled into the program through their palettes with their tower runs (I headcanon that alongside helping to restore the memories of those sanitized, running the Tower of Order also assists in helping people start working through their personal issues and that Benjamin is assisting as the drone during these runs, it's a long story that I don't plan on properly writing until I finish my octo expansion one), Jay ends up showing up in the program. Since Benjamin hasn't forgiven Jay for what he did, the two immediately start fighting, and progress on reconfiguring the palettes screeches to a halt as their constant bickering results in failed tower run after failed tower run. Eventually Cipher steps in to mediate a discussion between the two, and they're finally able to work out their issues with each other, pretty much making up entirely by the time they finally finish Jay's tower run. The two become friends again afterward, and after the events of Return of the Mammalians (I headcanon it happens after Side Order and the final bossfight happens during GrandFest), Jay confesses that he still has feelings for Benjamin and that he'd like to give their relationship another chance. Benjamin feels conflicted initially, as while he does also still have feelings for Jay he's also really happy with Taylor, but after talking it over with Taylor they decide that he'll give Jay another shot in a poly relationship. Jay agrees, and the three are still together to the present day.