The Goblin is the fourth troop unlocked in the Barracks.
The Goblin is the fastest ground unit in the game.
The Goblin’s first target is Resource Buildings, making them the ideal troop to deploy if your primary concern from a raid is collecting resources.
The Goblin deals double damage to Resource Buildings, Town Halls and Clan Castles, Gold Mines, Elixir Collectors, Dark Elixir Drills and storage for each). This means that he deals more than twice as much damage as Barbarians and three times as much as Archers to these types of buildings. The trade-off is his relatively low health, which is higher than an Archer but lower than a Barbarian.
Because the nature of the character is to attack Resource Buildings first (ignoring all defenses) they can be vulnerable to attack and should not be deployed without another type of troop (such as the Giant or Barbarians) as a meat shield.
Goblins prioritize resource buildings above all other targets, and will bypass all other types of enemy buildings and troops while any resource buildings remain on the battlefield. This is true even if they are under attack by enemy Clan Castle troops, heroes or Skeleton Trap skeletons. Note that like all troops that prioritize resources, Goblins consider the Clan Castle or the Town Hall to be resource buildings regardless of whether or not they contain loot; Goblins will preferentially target them in addition to causing double damage to them.
Once all resource buildings are destroyed, Goblins become like any other troop with no preferred target; they will attack the nearest building to them regardless of type, and will turn and attack enemy units if they become aware of any nearby.