F

F is the 6th letter of the alphabet.

Design
F's color is that of a dull red.

Quotes
"i don't fucking know shithead" F's first words (Comic 8)

"i ate a radioactive" (Comic 33)

"do we really have to climb the whole mountain?" (Comic 62)

Trivia

 * F is the 12th character to appear in Alphabex.
 * F, the 6th letter, appears for the 6th time in Comic 66.