Hunting grounds throughout Aden now have fewer Treasure Chests, but the rewards they give are better. They can only be opened through the Unlock skill or the newly added Maestro Key. (They can no longer be opened with Treasure Chest Keys.) The Maestro Key can be purchased from Grocer NPCs in each village or obtained through the Summon Treasure Key skill.
Treasure Chest rewards depend on both your character's level and the level of the Treasure Chest:
If your character is level 77 or below, you can receive rewards from Treasure Chests within six levels of your character level. For example, if you are level 77, you can get rewards from Treasure Chests of levels 71 through 83 only. If your character is level 78 or higher, you can receive rewards from Treasure Chests within five levels of your character level. For example, if you are level 78, you can get rewards from Treasure Chests of levels 73 through 83 only. If you get no rewards from a Treasure Chest, the chest self-destructs and disappears. If you are very lucky, you can obtain an Adventurer's Treasure Sack from a Treasure Chest. The three types of Adventurer's Treasure Sack you can receive are related to the level of the Treasure Chest.
Beginner Adventurer's Treasure Sack: One random D-Grade or C-Grade weapon.
Experienced Adventurer's Treasure Sack: One random B-Grade, A-Grade, or S-Grade weapon (excluding Dynasty).
Great Adventurer's Treasure Sack: One random Dynasty, Icarus, or Vesper weapon.