On The Boys, Homelander is the most powerful superhero on the planet. He has nearly all the abilities of Superman, including flight, invulnerability, super-speed, strength and heat vision. Those powers make him truly unstoppable, and yet, Billy Butcher and his team have made it their mission to take down the villainous Supe.
The task is much easier said than done, considering they are regular, fragile humans who don't stand a chance when going toe-to-toe with Homelander.
But like Superman, Homelander has a weakness. For the DC superhero, it's Kryptonite, the radioactive rock from his home world, but for Homelander, it's something less substantial. It's more of a concept one that's used to great effect against him in the Season 2 finale.
From the start of The Boys, it was clear that affection, however misguided or twisted it could be, was Homelander's weakness.
Homelander is a vile and twisted character who comes alive in the public eye. Deep down, he's a true villain, but, whenever cameras are filming and people are watching, he does his best impression of a bright and hopeful hero.
More importantly, The threat of exposure forces Homelander to stand down and that is his only weakness.