Spiritmasters play the debuff role in groups. They use their spirits and spells to wear down enemies to make them easier for high DPS classes like the Assassin to kill quickly. They can also dispel a targets beneficial buffs. And one last skill that makes them invaluable to groups is that they can raise an items drop rate, which will give the groups more and better loot when enemies are defeated. The higher level the Spiritmaster is, the more powerful and varied types of elemental spirits are available for summoning. And once Last Chaos Gold is released, there will be a fifth spirit, race specific spirit that players can summon in addition to the base four elemental spirits. Elyos Spiritmasters will be able to summon a spirit pet that is a combination of water and wind, while Asmodian Spiritmasters can summon a spirit made of fire and earth.
They should always have some sort of spirit at their side to hold aggression and damage enemies. There is an appropriate spirit for different situations, so part of playing this class is knowing what elemental should be used for a specific situation. Fire spirits are used for melee combat, while water spirits deal out magical damage from range. Earth spirits specialize in defense, and finally, the wind spirits are used in magical melee damage. Spiritmasters control most of the spirits attacks and abilities, so they cannot use their pet to farm monsters while they go AFK and eat lunch or something.