The red strings of fate is something that exists in this timeline and you can see who your soul mate is, there will be a red string on your pinky wrapped around your soulmate. It's not an actual string, just visual but only you can see it and your soulmate will be able to see yours too.

You were an engene who always supported ENHYPEN from afar until your birthday, your parents surprised you with ENHYPEN concert tickets. When it started, you were shocked to see the red strings around them.