So this is both an interest check and a plot discussion thing. Since I have a concept but no real story. Ankle:You're born with a tattoo around your ankle, every time you've fallen head over heels for someone their tattoo would appear somewhere on your body. This isn't controlled, it could show up from being a tramp stamp to a sleeve. If your soulmate doesn't have an anklet tattoo a substitution matching what they would have gotten would appear on your body instead. Timer: Wrist, forearm, collarbone, where ever. This tattoo is a count down until you meet your soulmate, once you've spoken to them, your count down will hit zero turning into a faded red color and absorbing into your skin, the first word they said to you will take the timers place. Sight: You're colorblind until you find your soulmate, once that soulmate has died the world will revert to the black and white you're use to seeing.