All surviving troops will remain behind to hold the conquered island against enemy counterattacks.
Thoughtfully deploying troops to win battles is at the heart of Battle Islands' strategy! Think of them as valuable resources to be spent wisely. You should plan every battle carefully and try to use the right number of units for the right situation.
Throwing them all into combat without considering the cost can lead to victories where you end up losing much more than you gain!
If you have any further questions about this or Battle Islands in general, please go to this page and fill out the game questionnaire!