Zorn and Thorn definetly... But out of the main characters, (holds up shields to defend from flying objects), VIVI!!! There I said it, he's always sad to the point of me yelling "NOBODY CARES VIVI, GO OFF AND SLIT YOUR WRISTS SOMEWHERE!!" Seriously, I can't remember him ever being happy...

Interesting fact: Vivi is like, 66, which shows his name is also a number! Sorry just thought I'd bring that up, quite interesting.