The four Shrine Trials (Spirit Shrines) in Trails of Cold Steel II, much like the Old Schoolhouse in the first game, is also used as a means for testing Class VII. And also would go towards upgrading Valimar's sword, their catch? Overcoming the hard trials the Spirit Shrines present. The Terra Shrine is the first Shrine that Rean's team comes across just when they're about to head into the Garrelia Fortress and have their battle with Xeno and Leonidas, followed by the battle with the Kreuzen Province soldats.
All but the 4th Shrine, the Ignis Shrine, has a midway point. They're known for each of the 4 elements. Water (Ebel Highway area), Fire (Nortia Highway area), Earth (Garrelia Byroad area) and Wind (Nord Highlands NE area). Beating the 3 Tildawn bosses grants Rean 3 AP. But beating the real guardian nets the player the Zemurian Ore, the item needed to forge the most strongest weapon for Valimar.
The Proving Grounds as it's come to be, is the 2nd section of the dungeon in which is guarded by a seal in which Celine can only break. As such, Emma becomes a fixed party member during this arc.
- Note: Be sure you wrap up any loose ends with the day's side-quests. Completing one of these 4 Shrines will make all side-missions disappear.