The Red Robes are the members of The Inquistion. They take care of cheaters, cloners and people, that spam with personal messages or write abusive PMs.
They (Fernando Vidal, John Hawthorne and Luigi Vercotti) work as Cardinals at the Inquisition Headquarters in Stockholm. The Sentinels help them with reported messages, that aren't in the languages, they speak.
If you can't report through the official ways (“Report Spam” or “Report Abuse” for PMs or “Cheat Reports” in the official help for cloners), you can write them directly. You can also do this, if you've been punished with guilty conscience or lightning and are convinced that it wasn't justified.