The Seven (HOO)

The Seven is the friendship between Percy Jackson, Annabeth Chase, Jason Grace, Piper McLean, Leo Valdez, Frank Zhang and Hazel Levesque from the Camp Half-Blood Chronicles fandom.

Canon
The Seven are a group of heroes chosen from a prophecy, formed to finally unite the warring factions between the Greek demigods on the Eastside of the US and the Roman demigods on the Westside. While Annabeth was looking for a missing and amnesiac Percy, who had been welcomed by the Roman Camp Jupiter, Leo and his group were working on the Argo II to fly above the Atlantic and retrieve the Athena statue the Romans stole from the Greeks a few millennia ago, finally ending the animosity between their factions.

Percy is the son of Poseidon, Greek god of the ocean. He started dating Annabeth around 8 months before his disappearance, making her worried sick. He became close friends with Frank and Hazel during his time in Camp Jupiter. He later found out that he and Frank are actually very distantly related through Frank's ancestor Periclymenus. When the two groups finally unite, he sees Jason as his "bro". He eventually managed to impress Piper after a bad first impression from her point-of-view. He bonded with Leo last, but they found out that they actually get along pretty well regardless.
 * Percy Jackson

Annabeth is the daughter of Athena, Greek goddess of wisdom. She initially disliked Percy based on the feud between their parents, but eventually fell in love with him after getting to know him for 4 years, not thrilled about losing him after only dating for 8 months. Annabeth quickly became close friends with Piper. She also gets along fairly well with Hazel. She made a friend in Frank, for being one of the few people who was actually nice to him from the start.
 * Annabeth Chase

Jason is the son of Jupiter, Roman god of lightning. He started the series with no memory, though supposedly already being in a relationship with Piper, despite finding out that Piper's memories are fake, they actually dated for a while. Leo was also implanted with fake memories of being Jason's best friend, but they do get to befriend each other after getting to know each other properly. Jason was praetor in Camp Jupiter before his memories were wiped, he never wanted that much responsibility, greatly preferring his time with other lowly Romans like Frank and Hazel.
 * Jason Grace

Piper is the daughter of Aphrodite, Greek goddess of beauty and love. She was implanted fake memories of being Jason's girlfriend, but their bonding resulted in him genuinely falling for her. She was already friends with Leo before Jason was forcefully inserted into their lives, having a sibling-like relationship with him. She became close friends with Annabeth after being taken to Camp Half-Blood by her. She initially dismissed Percy as "unimpressive", having heard stories about his feats, but he managed to prove her wrong. She also became friends with Hazel shortly before they fought they parted ways.
 * Piper McLean

Leo is the son of Hephaestus, Greek god of the forge. He was implanted fake memories of being Jason's best friend, but managed to genuinely befriend him during their quest. He had already been close with Piper before Jason, but never pursued her, seeing her as something like a sister to him. Leo's desperate for companionship and flirts with every girl who crosses his path, but noted that Hazel is different, with her revealing that she was very close to his grandfather Sammy in her past life. Due to his own insecurities, Leo used to pick on Frank a lot, but him proving his skills in leadership quickly shut him up.
 * Leo Valdez

Frank is the son of Mars, Roman god of war. He had a crush on Hazel since first meeting her, unaware that she felt the same way, which eventually gave way to them becoming a couple. Once Percy Jackson arrived in Camp Jupiter, Frank quickly befriended him and eventually they found out that they are very distant cousins. Though he felt somewhat misunderstood by the others on the Argo II, Annabeth showed him kindness from the start, so he confided in her.
 * Frank Zhang

Hazel is the daughter of Pluto, Roman god of wealth. She was resurrected from the dead into a completely different time period, but quickly became attached to her future boyfriend Frank, giving her some normalcy. She also became friends with fellow outcast Percy once he arrived in Camp Jupiter. Once they finally meet, Hazel notices that Leo seems awfully familiar, realizing that he's the grandson of her former schoolmate Sammy, whom she had a crush on. She went on side missions with Piper and Annabeth, eventually considering them friends.
 * Hazel Levesque

Fanon
Whether the Seven are actually friends or just allies out of convenience is a somewhat heated topic in the fandom. Many lament that popular characters like Reyna and Nico were never officially included in the group, but giving them spotlight in the last book has mitigated these complaints somewhat.

Polyships between all seven are rare, but they do exist.

Fandom
FAN FICTION