In the game, you can raise the flag once every day. The chance of raising the flag is reset at 0 o’clock every day. You can get a random Buff or a reward after flag raising.
The Buff lasts until 24 o’clock the day and includes:
More gold in Normal Campaign.
More EXP in Normal Campaign.
Reward may be:
Resetting Chance of Infinite Challenge;
Challenging chance of Arena;
Plunder chance of Ocean Route.
Remember to raise the flag immediately after logging in every day. It can increase your EXP or Rewards.