Campaigns consist of normal and elite instances. There are 8 chapters for both types, and before you can attempt an elite instance, you’ll have to first complete the corresponding normal instance.
There are specific stages within an instance that drop Hero Soulstones. Once you’ve achieved 3 stars for a stage, you’ll be able to auto clear it repeatedly. Collect 10 Soulstones to summon the corresponding Hero. The Soulstones are also required to upgrade the Hero.
The number of Soulstones needed for each grade promotion is as follows:
Hint: Complete as many instances as possible to collect Heroes; the more Heroes you have, the easier it is to build up your might later on!