@Sinkai_rahl As a fullback, if he has vision over all the field, he can act as a playmaker. That way, he advises his teammates to move to certain locations for either offense or defense. A complete fullback would be one that is able to utilize vision for defense and offense. Even though fullback is a defensive player, a complete fullback is able to be both, defensive and offensive, while also being a playmaker so that he can know the opponents will do as he'll have experience with defense and offense.