Popo's manga / #Apocalypse(1)

V2ch5.5 Vol2.3 trigger warning ️ - seme rapes uke literally out of the blue V2ch5 - I thought they were childhood friends? But why did we suddenly get a weird suggestion that they were related? the mad scientist guy said that family members would have antibodies. So Ai survived being bitten and the scientist discovered that Hikaru had antibodies.......are they actually blood related????