In the new DLC for Borderlands 2, you will find a new type of currency called ‘Seraph Crystals’. These glowing items can be traded for the new Seraph-level rarity guns and relics in the town of Oasis, but you’ll need lots of them to purchase the full set. They’re rather rare, but there’s a small exploit you can use to get them faster if you’re willing to put in the work.
Once you’re finished with the main story quests and side-quests, the only way to gain Seraph Crystals is by fighting the two new Raid Bosses; Hyperius the Invincible and Master Gee the Invincible. Both drop crystals but the problem is that this quest can only be repeated once every 24 hours, so how do we go about this?
Simple. Once you’ve finished the quest(s), save and quit the game. Go offline, then change your console or PC’s date 24 hours ahead. Go back online, and you’ll see that the Raid Bosses will be available to fight once again.
You might want to try using this to beat Hyperius as he can actually be soloed (if you have good equipment). He only drops eight crystals to Master Gee’s 16, but the latter requires a party.