Norscan Trolls

 is a Norsca monstrous infantry unit introduced in Total War: Warhammer. Though temperamental and difficult to control, a Troll is a whirling ball of difficult-to-kill death.

Description
Trolls are malformed monsters whose lack of intelligence is as legendary as their great strength. They are greatly feared because of their unthinking ferocity and indiscriminate appetites. Like all their kind, Trolls can vomit forth the steaming contents of their guts, dissolving their victims with powerful acids and flesh-eating worms. They are also possessed of powerful regenerative abilities: lost limbs and even heads can grow back. However, Trollflesh is extremely susceptible to the mutating power of Chaos, and Trolls who have lurked too close to the Realm of Chaos find tentacles, screaming maws and even stranger mutations sprouting from their wounds.

Strategy
Trolls have very low leadership which leaves them prone to running away. Whilst this can be useful to allow them to regenerate, they are not dealing the damage you want them to deal. It's usually best to let your chaff infantry engage first before sending in your trolls to fight between the ranks. This way they can be protected from overwhelming damage and any chip damage they take can be regenerated, allowing you to get the most out of them. They are particularly vulnerable to missile troops and fire, the former being a significant threat when facing another player. As such, it's not a bad idea to hold them back for a bit until this threat has been dealt with or appropriately tied up. Having a hero or lord nearby can't hurt either, just make sure you keep them embedded in your troops. Trolls can be incredibly cost effective if used right, but require a degree of babysitting and micromanagement to get the most out of them.