Because a true hero does not let reality stop him.
He is fat, kind, witty and against violence. The last person you would expect to be a vampire
“Inn keeper, your best all around” hollared the newcomer jovefully; tossing gold onto the counter, “and for you bard” tossing him a small purse, “some lessons” he added with a wink and a laugh.
When the sheriff entered the inn the next day, he found a carnal house, with patrons either on the ground with green foam runnig from thier mouths or cut to pieces. 11 dead, and someone had sport with the barmaid before killing her.
Tomais Reives is always quick with a smile or a joke or to buy the next round. He dresses expensively with a lot of flash and always seems to be the life of the party.
He its like by almost everyone, he has only one little flaw; He likes to kill; a lot.
If he did it for some master, or for some dark, it might be better.
He just does it because be can.
A slight rustle of the wind... and it stands before you. A Unicorn, whiter and more beautiful than you ever imagined it. It has deep wonderful eyes, and you can't help but admire this creature. It came to have a look at you, and now it freely goes. You have not the heart to stop it, and it silently vanishes between the trees.
Note: unless specially needed, this encounter should never happen again.