Gates of Challenge is the name of a building that unlocks at Castle Lv. 15.
At the Gates, you can challenge Legends of the Past from each era to a 1:1 battle.
When you defeat the Legends, you can receive special rewards.
※ You can challenge up to 15 times per day.
※ There are 3 free chances to challenge, and you gain a free chance every 2 hours(up to 2 times a day).