WWE saved the biggest surprise for the end of SummerSlam 2025 when Brock Lesnar came out to a thunderous ovation from the New Jersey crowd. While fans can't stop talking about The Beast Incarnate's attack on John Cena, some juicy backstage details have surfaced about how his return came to be.After Cena lost his Undisputed WWE Title to Cody Rhodes, the latter cleared the ring so The Cenation Leader could soak in the reception at his last SummerSlam event. However, this was short-lived as Brock Lesnar's music soon hit, and he appeared for the first time since SummerSlam 2023.The former Universal Champion made his intentions clear by taking out Cena, setting the stage for a major match between the two long-time rivals. As per Sean Ross Sapp of Fightful, the legal issues surrounding Lesnar haven't been resolved yet. However, since he isn't being actively prosecuted or sued at the moment, WWE was able to bring him back to its programming.Following SummerSlam 2025, Triple H claimed that Lesnar was brought back at John Cena's insistence, who wanted to face him before retiring. It remains to be seen when WWE pits the two megastars against each other.