Well, for Kelvin:

He died at the hands of his closest friend, trying to defend his sister whom had been turned into a vampire. Up until that point he had been almost as fanatical as Aurora- seeing someone he loved turn had 'flipped the switch' in his head. Realizing his mistake, he tried to protect his sister and smuggle her back to the Dark world, and was caught halfway by his friend's patrol. His friend believed that Kelvin had become deluded and tried to reason with him, but had no choice but to order the crossbowmen to shoot when he drew his sword. Kelvin reawoke a day later, to find his sister staked out on the ground, baking in the sun. In the end though, he was too weak from bloodloss to help her or himself, and they both died. His friend reported him to have died an honorable death on the battlefield, as a favor to his family (who knew the truth) and to protect them from the shame of a traitor.

As a ghost he had become angry and irrational at what had happened, and it took a long time for him to cool off. In a way, his ghost self slowly became an entirely different person, as pre-death he had been a fairly simple man. It was death that showed him what truly mattered to him. His goal before reincarnating was this; creating a world where those he loved could be reincarnated on either side of the border, and live safe, happy lives.

This makes the story a bit tragic, as if he did follow a romantic path and fall in love, it may have brought about events that eventually resulted in him moving on to reincarnation- leaving behind whomever he had fallen for.