While The Boys is a series built on major twists, a huge reveal about the Seven in the comic's final arc drops the bombshell that they're secretly siblings. The original Seven - Homelander, Black Noir, Queen Maeve, the Deep, Jack from Jupiter, Mister Marathon, and the Lamplighter - are the strongest supes in the world, but they hide a dark secret. Rather than being created by alien mentors, mystical blessings, and mythic tragedy, they were all grown in a lab as part of a long-con plan to turn them into profitable military assets.
This reveal gains new significance when, in The Boys' bloody Battle of Washington, Black Noir removes his mask to reveal he's an exact duplicate of Homelander. Created using the same process of DNA-tampering, Black Noir was designed as a failsafe if Homelander got out of control, and is the only person powerful enough to kill him. However, a detail that's easy to miss is that Black Noir isn't just identical to Homelander: they're literal twins.
This is fully explored in The Boys #66 (from Garth Ennis and Russ Brain), when - following Homelander's failed superhuman coup - the details of his creation become a matter of public record. In a discussion on the radio, many of Vought-American's sins come to light, including the scale of their operation - which euthanized 60% of the superhumans it created - to the fact that all of the Seven were directly derived from Stormfront's DNA. While fans knew that Homelander was a genetic experiment based on the powerful fascist supe - and reason dictates Black Noir was too - it's only here that it becomes clear that the Seven were all created from the same man's DNA.
The Seven Are All Stormfront's Children
This means the original Seven were all half-siblings - a fact they never knew, despite the brutal rivalries and even romances that sprang up between them. Given Vought-American's superhuman creation process kills the women who bear their genetically-manipulated Supes, it's impossible the Seven share the same mother, but each is a variation on Stormfront's DNA, albeit with some tampering to create different power outcomes. The only member of the team who would ever learn this fact is the Deep - the sole member of the original Seven to survive the series, and likely horrified to find out that the dysfunctional superteam were effectively a group of clueless siblings.
Why The Boys Turns the Seven into Siblings
Throughout The Boys, the story uses Nazi symbolism to depict the Supes, framing them as the Americanized form of the notion of the übermensch, with Homelander a literal Aryan superman. In tying all of the Seven to Stormfront, the series once again draws a connection between Nazi ideology and modern superheroes, literally depicting Homelander's team as the next generation of the Nazi dream, thinly veiled to appeal to the company.
The Seven are a Tragedy from Beginning to End
The Boys keeps revealing the horrors of its world to the very end, but the fact that the Seven were so closely linked is a true tragedy for a group of people whose evil often stemmed from feeling disconnected from the world around them. It would be inaccurate to call the Seven a 'family,' but it's particularly perverse and disturbing that the bullying, callous group were among their half-siblings all along, and might even have found connection and meaning if they'd known. The Boys has little interest in the pathos of its supes, but in presenting Homelander and the Seven as secret siblings, it brings to culmination the theme of how far corporate interests will go to turn a profit, and the complete absence of any moral considerations in Vought-American's effort to increase its power over America.