Status Updates From Dr.STONE 6

Senku's father, Byakuya, returns to Earth after humanity has been petrified. Meanwhile, Senku and his friends are attacked by assassins from the Tsukasa Empire. In the midst of this emergency, they begin developing the ultimate weapon, the "Blade of Science," to protect the village. The Katana is what was made. They made it by folding steel over and over, then sharpening it.

so his dad is dead...he's actually adopted and now there's another cool killer who we're gonna turn his devotee on him