A boss usually has enough defenses that it would be impossible to defeat it outside of the designed raid size parameters for the particular boss. For example, a normal team size in a game may be 5 people, but a raid for a particular boss may be up to 20 or more people. A normal team size wouldn't be able to handle the level of damage that the boss can do, therefore it is necessary to have enough people so that the damage dealt by the boss is manageable. This can be done through a large enough group of healers and other damage negation classes. Another benefit of an extraordinarily large group of people are stacked buffs, where the damage dealing classes are buffed, through an increase in damage or accuracy, by other classes so that the damage dealt to the boss is enough to kill it.
Por favor, espere.
