Casting is the act of providing live commentary of a game or replay, using the in-game broadcasting function to speak to audience members watching the game. Casters take on the responsibility of directing the in-game camera, providing live audio, and entertaining the audience. While casts are generally made in-game, it is possible to cast a game through a stream or through recorded videos. Dota 2 has built-in support for up to 6 broadcasters in private Lobby games.
Casting is done for a variety of reasons:
- To entertain through commentary and charisma
- Educate spectators on game mechanics they may not be familiar with
- Teach new players about the function of the game
- Help spectators understand the motives of the players
- Point out details that may not be obvious at first glance
- Interact with the audience in more meaningful ways
- Translate game events to a foreign audience
Casters can't interact with the players in-game - only with the audience view. Casters have the ability to speak to the audience, adjust the in-game camera, ping the map, and draw on the minimap. Once a game has started, a caster can't join a game in progress - though they are allowed to if they were given broadcasting privileges in the lobby formation.
Most tournament games have at least one caster broadcasting, as well as a live stream for spectators outside the Dota 2 client. Casters usually cast alone, but multiple people can cast in one broadcasting channel at one time. In this case, the additional casters are known as co-casters.
Many professional players will cast casual games in a live stream, allowing them to interact with their fans while giving them a view on how professionals play. Professional teams may also do this if they want to showcase what practice sessions are like for the group, though tournaments usually disallow streaming while playing in-game.
Some casters go on to develop a fanbase of their own regardless of what they cast, which leads to increased popularity for any tournament that hires the caster.