Necromancers are undoubtedly the best soloing class in the game. They can solo in several ways that involve no danger to the player. The most famous is their ability to reverse kite. This ability entails pulling an enemy with snare. While he is approaching, the Necromancer can cast DoT spells, followed by fear which leaves the enemy slowly walking away from the Necromancer. The pet should then attack the enemy and by the enemy dies shortly thereafter, with no damage taken.
Necromancers can also solo by simply kiting, which is basically doing the same thing as reverse kiting, except without fear. This is better in cramped situations and where you need to control where the enemy runs.
In groups and raids, the Necromancers usefulness increases as the duration of the battles increase, as their DoT spells are able to take full effect and do their maximum damage. While their fear and snare effects aren’t nearly as useful here, they also have the ability to pump their mana into other players, specifically the healer. This can often save lives, as a healer with no mana is useless and players can easily die.