Fate Isn't Always Kind

Makoto has lived his life without any knowledge of who his soul mate is, all he had to show he had one was a dolphin and whale symbol on his hip. How will he react when he finds his soul mate with the matching symbol, who isn't only a baby, but his best friend Rin's newborn son? Based off of a Tumblr prompt where a doctor helps deliver their soul mate as a baby. Just for laughs.