fourth wall character 

A fourth wall character is a character that serves a specific purpose. By its very nature it is aware that it is a character, to some degree, and thus is not confined by the rules that usually confine them. They tend to use things like out of character knowledge and some degree of immortality as a part of their duties.

"I had a Random Encounter today. Strange character; he can't do anything but create monsters and NPCs, but he can't be effected or effect us."

"The Professor? He just goes around and grades RP, corrects spelling and grammar, and in general tries to help. Sometimes violently. Just take it with a grain of salt. If you try to kill him, he won't die anyway. He's a fourth wall character."

fourth wall character by Random-Mun May 6, 2014