Gamemaster

A Gamemaster (GM, also known as game master, game manager, game moderator or referee) is a person who acts as an organizer, officiant for questions regarding rules, arbitrator, and moderator for a multiplayer role-playing game. They are most common in co-operative games in which players work together and are less common in competitive games in which players oppose each other. The act performed by a Gamemaster is sometimes referred to as "Gamemastering" or simply "GM'ing".

The role of a Gamemaster in a traditional role-playing game is to weave the other participants' player-character stories together, control the non-player aspects of the game, create environments in which the players can interact, and solve any player disputes. The basic role of the Gamemaster is the same in almost all traditional role-playing games, although differing rule sets make the specific duties of the Gamemaster unique to that system.

The role of a Gamemaster in an online game is to enforce the game's rules and provide general customer service. Also, unlike Gamemasters in traditional role-playing games, Gamemasters for online games in some cases are paid employees. For both Ragnarok Online and Ragnarok Online II, all Gamemasters are paid employees that are only hired from outside of the games via official career sites. Never will a Gamemaster hire from within the games they host.

Ragnarok Online
Unique to RO, Gamemasters can be denoted by their own sprites, which behave as special costumes that are tied to GM-flagged accounts. Gamemasters possess a wide variety of abilities that are off-limits to players such as: Gamemasters usually appear in-game in order to manage official events, moderate player-run events, investigate reports, and test.
 * teleporting a player character wherever they want
 * invisibility
 * summoning monsters without the use of Dead Branches

Lately, there's been an ongoing scam in which players impersonate Gamemasters to unsuspecting players in order to gain access to their accounts. Victims would willingly hand over their account information to the scammer, who then proceeds to take over the account by changing passwords and emails. Although compromised accounts can be returned to the original owners, the process of investigating each account and verifying ownership can take several days to complete. As such, players are advised to investigate anyone claiming to be a GM. There are a few way to verify a real Gamemaster.
 * When real Gamemasters whisper you, a yellow message (similar to server-wide messages) will pop up on the top middle of your screen.
 * Ask the Gamemaster to show themselves in their Gamemaster sprite. A real Gamemaster will never refuse this request.
 * A real Gamemaster will NEVER ask for an account's username and/or password for verification. They have no need to ask for such vulnerable information and would rather ask for more in-depth information for verification.
 * Real Gamemasters have no need to require a player to install 3rd-party programs such as TeamViewer or Skype in order to verify information, as the Gamemasters already have access to account information from their end.

Valhalla Prison
When a player comes under investigation, Gamemasters will teleport the player to Valhalla Prison, which is colloquially known as the GM Jail. The prison is a specially rendered in-game dungeon where players are interrogated and possible bots are investigated. It consists of both large prison cells and small prison cells for all investigative purposes.

Valhalla Prison is a separate map that can only be accessed by Gamemasters. There is no way to go to the prison as a player outside of being investigated by Gamemasters.

Ragnarok Online II
In RO2, Gamemasters have different GM costumes and simply have a "GM" moniker above their characters. They possess the same abilities as RO GMs, but lack a jail for investigative purposes. Verifying a Gamemaster in RO2 is the same as that of RO (aside from the yellow announcement text), so be sure to follow the procedures in order to not fall for players impersonating Gamemasters.