Artifacts and souls

Mobs drop common souls upon death. These souls can be upgraded on a crafting table into iron, gold, and diamond tiers, and subsequently awakened on a special upgrader table to fill them with elemental powers - Water, Light, Earth, Cosmic, or End.

Tools and Crushers: Heavy tools are added (such as the Earth Hammer and Cosmic Crusher) to break blocks in a 3x3 area, as well as universal elemental multitools.

Relics and Flora: The Dodge Ring grants a chance to dodge attacks. You can also craft the Sword of Light, Staff of Seas, and End Amulet, or collect Void Berries that grant night vision.

Soul Side Effects: Eating mob souls grants their properties, which can cause you to explode (from a creeper soul) or burn in the sun (from a zombie or skeleton soul).

Boss Summoning (using the BossSummoner item):

Soul Skeleton — summoned by clicking the item on a built tower made of a diamond block, quartz, and soul sand. It drops its soul to craft the Soul Spear weapon and armor with fire resistance.

Upgrader-Spider — summoned by clicking the item on an upgrader block. It drops a poisoned soul to craft a poisoned dagger.