Achan's Sin (Pale Green) interrupts the ability of Ship to Cypress because ITB interrupts the last enhancement, if played by an opponent. When it interrupts, it suspends the ability until Achan's Sin resolves, meaning the banded character is not in battle. If Achan's Sin resolves and there are no heroes left in battle, the battle is over. The ability does not reactivate, because:
1. It must still be in play (it has been removed from game at resolution).
2. A hero it can be played on must still be in battle (if none remain, even if it were protected from removal, it could still not activate.