There are various items you may receive as loot from battles which allow you to upgrade your characters.

Shards
Characters can be upgraded using two types of Shards: regular Shards which grant bonus experience to your character, and Evolution Shards which allow you to evolve your character to the next Star Level.

NOTE: Characters must be at the max level for their Star Level before they may Evolve.

Talismans
Talismans are equipped onto your characters and are the primary method to improve their stats. You can increase any stat your character has as well as grant them additional abilities. Determining the stats your character benefits most from, then equipping talismans that boost those stats is key. Talismans can be unequipped so you may use them on a different character if you wish.

NOTE: If the talisman slot on a character is coloured, you may only equip a talisman of the same colour in that slot.

Runes
Talismans can be upgraded using two types of Runes: regular Runes which grant bonus experience to your talisman, and Evolution Runes which allow you to evolve your talisman to the next Star Level.

NOTE: Talismans must be at the max level for their Star Level before they may Evolve.