Prestige

Prestiging is an accomplishment throughout AllstarScape. It is used to show off how determined you are at playing the game. To prestige, you must talk to Vannaka at home, in the small hut to the north of the home teleport, you also must have 99 in every skill, and 120 in Dungeoneering. You can choose the option to show your prestige level in your title, it is in roman numerals. Along with the ability to show off your prestige level, there are also perks to getting higher prestiges.

Prestiging doesn't stop at 15, only the perks stop at 15. Meaning that if you really wanted to, you could prestige past 15, although you wouldn't get any kind of reward from it.