Spirit Hunters: Infinite Horde

All the character unlock achievements are the same. Magnus and Vivian are unlocked by default. For the other 6 Just collect enough Runes, Crystals, Ember Cores and Shadow Souls to progress through the Divinity Web and then use Crystals to unlock the Nodes that have the characters. They range from about 50 crystals to 500 crystals to unlock. The last 2 McDiggins and Sickle are 500 each. Once the node is purchased the achievement will unlock.