You need Stylish for this style
If your icons do not change initially click the stylish icon and then save there should be a 1 on the Stylish icon.
If you do not like a particular icon surround the text with a */ /* comment

Example:
*/
.role-NAME {
background: transparent url('CODE HERE') no-repeat scroll left top !important;
}
/*

Original Code http://www.epicmafia.com/user/41673

Leave feedback at http://www.epicmafia.com/user/63167 about which icons should look awkward or out of place or simply could be better.

5.18.12
Icon Differences

Village
Villager, Doctor, Nurse, Sleepwalker (http://www.epicmafia.com/user/40448) , Governor, Town Crier, Loudmouth (http://www.epicmafia.com/user/71438), Priest, Virgin, Oracle, Enchantress, Granny (http://www.epicmafia.com/user/41673),Sheriff (http://www.epicmafia.com/user/41673)
Chef (http://www.epicmafia.com/user/52179)

Mafia
Yakuza, Godfather (http://www.epicmafia.com/user/41673), Tailor, Hooker, Disguiser, Actress, Fiddler (http://www.epicmafia.com/user/40448), Forger, Ninja

Third Party
Fool, Lyncher (http://www.epicmafia.com/user/41673), Angel, Clockmaker, Prophet, Mastermind