Vanguard: Saga of Heroes is a high fantasy-themed massively multiplayer online role-playing game (MMORPG) created by Sigil Games Online, and now developed and run by Sony Online Entertainment. Originally, the game was co-published by Sony Online Entertainment (SOE), and the company producing it, Sigil Games Online. The game was released on January 30, 2007, with an early access date of January 26, 2007 for pre-order customers. On May 15, 2007, it was announced in a press release that Sony Online Entertainment had completed a transaction to purchase key assets of Sigil Games Online, including all rights to Vanguard

As with any MMORPG, Characters in Vanguard: Saga of Heroes are a player`s avatar in the game environment. Twelve characters can be created on a regular account (increased from 8 in GU6). At creation, the name, gender, race and adventuring class of the character are chosen and will not be changeable later. The character`s appearance is also chosen, but can be modified by the player at any time thereafter, from the character selection screen. After his or her creation, the character can start play either in the starting area of his or her chosen race or in the trial zone called the Isle of Dawn. The character can pick a crafter class and two harvester skills within the game, but is not forced to do so.

There are 19 races, listed in the geography section below. Races differ in appearance, special abilities, diplomatic affinity, and adventuring class selection. To help distinguish the races (aside from looks), every race has also one special active ability that unlocks at a certain level (between level 1 and 12, depending upon race).

The core concept of Vanguard`s class system is the design for grouping. All of the classes can perform one of the three major MMORPG roles: tank, healer, or damage dealer. All tanks and healers are supposed to perform their job about as well as their peers, although in specific situations one class will be better than another. DPS classes vary in their roles: the Bard, while it belongs to the offensive fighter group, is more of a support class and crowd control specialist than a pure damage dealer. Various classes come with point systems that allow the usage of special abilities. Monk, Disciple and Blood Mage can increase their points very fast in battle though the usage of other special abilities and have to take care of their points all the time. Paladin and Druid mostly just regenerate their points over time, so they use them much more rarely and for more situational abilities such as area heals from the druid. Rangers have the ability to put up special effects on their opponents through the usage of special sequences of attacks. Disciples can do the same for shorttime single target buffs called endowments for an ally.

Player vs Player (PvP) is possible on the Sartok PvP server, or on PvE servers using the /duel command (you do not gain any reward for winning a duel), but the adventuring classes have not been designed with this in mind, and this aspect of gameplay is not currently a priority for the developers. Vanguard classes are therefore not balanced with PvP in mind, and some classes are more capable in this regard than others. For example, the maximum damage of a single attack is restricted to 40% of the maximum hitpoints of a attackee, but certain classes can combine multiple instant attacks, resulting in the possibility to kill other classes in one turn with no chance for the victim to fight back.