Red String of Swords

Every Child is born with a tattoo of something like a flower or cloud. The tattoo determines the child's soulmate, by whoever has a tattoo in the same spot as you but the opposite design is you soulmate. For example if a person has water droplets on their wrist and meets someone with fire on the same wrist they become each others soulmates. However if you find someone with the same exact tattoo as you on another part of them, that person become you best friend soulmate.