Every 5 levels, the boss has a chance of giving better rewards. First entry in a day is free and it costs 3 Purgatory keys to double the rewards (50bb each).
As of recent patches, all revives are free. In previous patches only one was free and the subsequent costed 25bb.
- Having cleared Lvl. 100 of the Forgotten Catacombs.
- Being lvl80 and having completed Class Advancement.
Each level gives a consistant reward in term of gold and XP (is XP affected by the catacomb's 4th card 10% bonus ?).
- Lvl 1 : 50k gold / 242k xp
- lvl 2 : 50k gold / 262k xp
- Lvl 3 : 50k gold / 286k xp
- Lvl 4 : 50k gold / 308k xp
- Lvl 5 : 100k gold / 330k xp
- Lvl 6 : 75k gold / 352k xp
- Lvl 7 : 75k gold / 374k xp
- Lvl 8 : 75k gold / 396k xp
- Lvl 9 : 75k gold / 418k xp
- Lvl 10 : 150k gold / 440k xp
- Lvl 11 : 100k gold / 462k xp
- Lvl 12 : 100k gold / 484k xp
- Lvl 13 : 100k gold / 506k xp
- Lvl 14 : 100k gold / 528k xp
- Lvl 15 : 200k gold / 550k xp
- Lvl 16 :
Additionally, each level appears to give one of the following :
- Crystal shards
- x10 at lvl 1 - 9
- x20 at lvl 10 - ??
- 2x lvl 70 legendary stones (variation unknown ; seen at lvl 6, 11, 14)
- 1x lvl 80 legendary stone (variation unknown ; seen at lvl 2 and 3)
- 5x lvl6 crystaloids (variation unknown ; seen at lvl 4 to 12 so far)
Levels multiple of 5 have a chance to drop one of the following items instead :
- 1x lvl 1 RES crystal (seen at lvl 5, 10 and 15)
- 5x Vulcan Stove (seen at lvl 15)
The R2 guide hits at the following other rewards : Gem synthesis formulas, Will crystals.