... I prefer Loki's name to be spelled with an I, though. It looks better, in my opinion >.> But apparently, Hiro Mashima got the name 'Loke' from the Norse god of the same name o____o I always thought that it was spelled with an I, but whatever.
I'll just type up the whole page which describes the origin of their names:
"The main character is named Natsu. This is the truth. The name of my last main character was Haru (Japanese for "spring"), and after Haru comes Natsu (Japanese for "summer"). Sorry. Happy was originally named Freyr. It's the name of a Norse god. That was too much for him, so I changed it to something more appropriate. Lucy is from a Beatles song. At the time I decided to name her, the song was running through my mind. I don't remember exactly what I was thinking when I named Makarov, but I recall wanting something that sounded vaguely Russian. Mirajane is the name of a character I came to know in an online game. I don't remember where I got Gray. (Ha ha!) The name of Erza came from the heroine of my ancient short story "Fairy Tale," Eru. Loke is named after the Norse god. I wanted a somewhat cute name for the Elfman character, so I came up with that name. Cana comes from the arcana of tarot cards. Hmm. Looking over, I get the feeling that there are a lot of names I didn't think too hard about."
My hands hurt >.>
I totally can't imagine Happy as Freyr xD