Have a fight over Relic task separate from the current realm task. The only objective is to fight over relics in a frontier. Have it rotate with the Keep Task.
Relic Task - Put relics back in relic keeps. New system where the task rotates between each frontier. Take Midgard relics. If your realm captures the Midgard relics you get the full 10% damage bonus until the next Relic Task. When a new task starts you lose the bonus, but keep the relics in your relic keep. Have it rotate Hibernia - Albion - Midgard. Have 2-3 Relics tasks per day.
Relic Task - Put relics back in relic keeps. New system where the task rotates between each frontier. Take Midgard relics. If your realm captures the Midgard relics you get the full 10% damage bonus until the next Relic Task. When a new task starts you lose the bonus, but keep the relics in your relic keep. Have it rotate Hibernia - Albion - Midgard. Have 2-3 Relics tasks per day.