Backup

Backup, also known as reinforcements, refers to reserve enemy soldiers that often appear on the field during Alert mode or caution mode, usually appearing if the enemy present is dealing with the player and are having trouble taking the player character down, or are otherwise aware of suspicious activity and notifying their commanding officers of the suspicious discovery. Depending on the situation and environment, the enemy's HQ/command post, when asked for backup, will either meet the enemy soldier's request and send in reinforcements, or otherwise refuse, citing that they are unable to spare any reinforcements before telling them that they're on their own for the time being. Reinforcements that are summoned tend to be more difficult enemies to take down.