The game offers various ways in which these items can be upgraded.
Level Up[edit | edit source]
Schematics and People (Heroes, Survivors and Defenders) can be increased in level by spending Experience on them. Each item can be leveled up to its current maximum level. Increasing the level will improve stats and Power Level.
The type of Experience (short: XP) used depends on the item. Weapon and Trap Schematics use Schematic XP, Survivors and Lead Survivors can be leveled up with Survivor XP, Heroes and Defenders require Hero XP.
The amount of XP required for level-up increases linearily with level. For each item type and rarity, there is a 'Base XP' amount which is the first level-up cost (from level 1 to level 2). For each additional level-up, this amount is again added to the previously required amount. Therefore, the required XP to level an item from level X to X+1, is given by
BASE_XP * X.
To calculate the cumulative amount of XP required to level an item from level X to level Y (disregarding Evolutions), the following formula can be used:
BASE_XP * ( Y*(Y-1) - X*(X-1) ) / 2
Items inside the Collection Book can also be leveled and evolved. This further increases the Collection Book level.
Evolution[edit | edit source]
Items start at Star Level 1 with a maximum level of 10. Increasing the Star Level will improve stats and Power Level and increase the maximum level by 10.
Resources used in Evolution include:
- Pure Drop of Rain
- Lightning in a Bottle for 3-Star Evolution and above
- Eye of the Storm for 4-Star Evolution and above
- Storm Shard for 5-Star Evolution
- Training Manual for People
- Trap Designs for Traps
- Weapon Designs for Ranged Weapons and Melee Weapons.
The Evolution costs can be read from the following tables:
Upgrading item rarity[edit | edit source]
The Rarity of Heroes and Schematics can be increased by one step in rarity at a time, provided that:
- The item is of Epic or lesser rarity
- There is an equivalent item of higher rarity in the game
Upgrading the rarity requires Flux:
|Target rarity||Flux cost|
|Uncommon||10 Rare Flux|
|Rare||100 Rare Flux|
|Epic||100 Epic Flux|
|Legendary||100 Legendary Flux|
Flux can be bought in the Weekly Item Store.
When upgrading rarity, the item level is preserved. To account for the greater amount of XP and evolution materials necessary to level-up and evolve higher-rarity items, the difference in these resources must be paid to complete the rarity increase (XP for evolutions being an exception). The rationale behind this mechanic is that it should make no difference in resource consumption whether an item is first leveled and then 'fluxed', or vice versa.