Just providing the Location for each of the Cruz Knights for Alaine’s quest progression.
Cruz Knight Locations for The Heart of Darkness
First Location: Garden of Pruners: Red Rose Garden
Second Location: Groaning Valley: Eastern Tower 2F
Third Location: Crystal Lake: To the east of the Church where you find Matra
Fourth Location: Forest of the Blackbeast: On entering follow the path to the east
Fifth Location: Basin of Decay: start from the Pyre “Connecting Bridge” & follow the boardwalks north instead of east
Sixth Location: Fortress of the Midnight Sun: From the Start head down the 1st flight of steps, then head all the way to the west without going further down, you should come to a broken walk way & a path north that leads to the soldier.
Seventh Location: Castle of the Midnight Sun: Teleport to Pyre, “大図書館” & head up the stairs to the previous zone, just to the east will be the soldier.
This is just here to help the people that got stuck like I did.
