Izuku and Shinso are twins to the powerful villain, AFO/Hisashi, a hero killer, Stain, and someone who's considered human but at the same time, considered a Nomu, Kurogiri/Oboro.
Two people have heard of the twins, Inko and Toshinori Yagi. Inko was not capable of having children of her own, which is probably why she originally stole the two twins. Izuku would stand up for his twin, despite his twins' protest.
When Stain woke one day to his sweet angles gone, he whimpered loudly, making his other child, Tenko, come in and rush over to him. He asked what was wrong and his papa told him in a shaky voice that his twins were gone. Now, Tenko, was upset and vowed to find them.
When the others found out, they went to look for the twins. That search will never stop until those two were found. Izuku had lost his spark when he was ten. He was also very innocent unlike his brother. He tries to not infect his brother with it though. When the twins were about 14, Toshinori's old friends were coming. More specifically, Hawks and Midnight.
When Midnight and Hawks get to the house, they were hit with an omegas scent. And they were just at the door, not inside. Hawks knocked, a male omega who's spark was gone answered. That was already a red flag for the two heroes.
What happens when Izuku and Hitoshi find their mates? Hitoshi wanting his brother and himself out. What about when Izuku saves a hero from a Nomu? The said hero he saved, one of his mates? What if the hero tried to follow him but lost track of him and his scent? What will the villains do when someone took down the Nomu and realize that they seem familiar to the said villains? What if Izuku saw his other mate in the shadows one night? What if he got away from that soulmate as well?