Tanks are tough heroes who can take extreme damage and can dish out crowd control at the cost of damage. A tank's sole purpose is to engage, hold the line and take extreme punishments rather than kill the enemies. They can lock down targets, preventing them to escape thanks to their persistent controls.
In addition to strong base defense, tanks tend to strengthen their defensive capabilities through skills, Arcanas(Armor and Magic Armor, Health, Cooldown Reduction) , items and Enchantments(Afata). However, tanks usually can't handle themselves in single combat due to lack of continuous damage, and their capabilities are quite limited by their lack of mobility.
As tanks can handle burst damage very well, they tend to succeed against assassins and most mages, but their vulnerability to continuous damage puts them at a disadvantage against warriors and marksmen.
List of tanks
Controls are offensive tanks. Controls lead the charge for their team and specialize at bringing the action. Their explosive team fight initiation seeks to catch enemies out of position while allowing allies to follow-up to devastating effect.
Protectors are defensive tanks. Protectors stand steadfast, seeking to hold the line by persistently locking down any on-comers who try to pass them. Protectors keep their allies out of harm’s way and allow them to safely deal with enemies caught in the fray.