Power Credits
Power Credits are the game's main general-purpose currency. They are used across character progression, promotions, upgrades and other systems, so they are usually the most flexible resource for a developing account.
Nth Metal
Nth Metal is used for Nth Metal packs and Metal-era progression. The main regular sources are Survivor, Online Battle rewards and Phantom Zone. Read How to Get Nth Metal for a farming breakdown.
Valorium Alloy
Valorium Alloy is used to upgrade Metal character special attacks and is strongly tied to Phantom Zone progression. It is not interchangeable with Nth Metal: owning a Metal character and fully upgrading that character are two different resource problems.
Energy
Energy controls how long your characters can continue fighting before needing recharge. Large Energy balances are useful for repeated Online Battle or progression sessions where waiting would otherwise slow you down.
Gear Shards
Red, Blue, Green and Purple Gear Shards are used for gear upgrades and evolution. Gear progression becomes very expensive when you are evolving multiple high-value pieces, so shard supply is an important late-game resource.
Alliance Credits and Last Laugh Tickets
Alliance Credits belong to their own store/progression system. Last Laugh Tickets are tied to Survivor's Last Laugh reward system and are especially relevant for augment progression.
What should you prioritize?
- Need general upgrades or direct promotions? Power Credits.
- Building Metal characters? Nth Metal plus Valorium Alloy.
- Building premium Gear Cards? Gear Shards.
- Grinding many fights? Energy.
Currency packages
SlepyInjustice lists individual currencies and a multi-resource bundle on the Currencies page. Choose the resource that matches the progression system you are trying to finish instead of adding currency you do not currently need.