[Paladin2]

"It might just be the letter “O,” but it also resembles a crystal ball, a favorite of hypnotists."

HarpO already owns the O. Zer0's l0g0 always reminds me of a zer0.

[mnehring]

It could be any single item, a letter, a symbol, whatever. It is nature to unite behind your team’s flag. The simpler the flag the better.