Venomous Fateful String

A new power was given to the world out of seemingly nowhere. For decades, these people have been called Stringers. People with powers coming from a red string. Our protagonist gets attacked by evil stringers named the serpents and survives by unlocking his hidden power. With his current friends and new ones alike, his goal is to beat their leader. But relax along the way! Warning - this story gets very heavy. at any point you feel uncomfortable, I would advise against continuing further