Quick answer: The Training Grounds Key is a Story Item rewarded for defeating the Chief Disciple of the Seven-Stars Formation in the Mandate Encampment, alongside his Phantom Edge, Swordsman’s Summon.
Training Grounds Key card
The Training Grounds Key is listed as a Story Item in Phantom Blade Zero. Its card reads: “A key hanging from a yellow jade ring. Opens the main gate to the Training Grounds.”
The card pops up over the fight arena as soon as the reward is granted. The Training Grounds Key is handed over after the Swordsman’s Summon Phantom Edge.
Where the Chief Disciple fight is
The fight takes place in an open dirt arena inside the Mandate Encampment. You can recognize it by the burning wooden watchtower, which stands like a pyre, and the bodies lying across the ground.
Walking into the arena starts the formation fight. A short scene plays first, showing a masked troop of white-robed swordsmen. After it ends, the health bar “Chief Disciple of the Seven-Stars Formation” appears, and his swordsmen circle around him.
The fight has two stages. Once the first health bar is empty, a second one appears, labeled “CHIEF DISCIPLE, SWORD OF DESPAIR”. For his moves and how to handle both stages, use the Chief Disciple boss fight breakdown.
What you get from the fight
The rewards appear in this order after the second stage ends:
- The Swordsman’s Summon Phantom Edge card, with the prompt “Equip the new Phantom Edge now?”
- The Training Grounds Key card
- The “Sword Against the Seven-Stars” trophy
When the battle ends, a blue memory flower shines above a fallen fighter on the arena floor. This flower is included in the Seven-Stars Formation memory flowers rundown.
Tower Rear Exit bell
After the Chief Disciple falls, the Tower Rear Exit bell appears in the arena. There’s no bell at that spot before the fight. Its shrine shows an E prompt when you walk up to it.
Rest at the Tower Rear Exit bell once you have the key. That saves you from crossing the camp again on your way to the Training Grounds.
What the Training Grounds Key opens
The key’s card reads “Opens the main gate to the Training Grounds.” The multi-wave fight inside the Training Grounds is covered in the Training Grounds yard fight guide. For the way onward, see how to get into the Mirage Estate.
To see what every other lock in the game needs, check the full list of Phantom Blade Zero keys. The Mandate Encampment collectibles list covers everything else in the region, including the Training Grounds Key and the Mandate Valley Gate Key.
