Pathfinder: Wrath of the Righteous allows you to cast aside all celestial and mythical powers to be an epic mortal hero. You must unlock the Legend Mythic Path to do this. You can learn how to unlock this Mythic Path below.
This late-game Mythic Path is nigh unmissable, so you don't have to do much to unlock the Legend Mythic Path. Once you reach Mythic Rank level eight you will have to choose to become a Legend. This choice is always present regardless of what actions you take throughout the game.
Related: How to unlock Gold Dragon Mythic Path in Pathfinder: Wrath of the Righteous
While other Mythic Paths grant you new spells and features, the Legend Mythic Path works differently. Choosing this path will also lose all feats and abilities from other Mythic Path. It doubles your level cap from 20 to 40, though you can still only take 20 levels in a single class. This allows you to create powerful class combinations of martial and spellcaster classes.
Additionally, you gain a +4 to all of your stats as well as accelerated experience gain. You will also gain a legendary resistance to corruption. This allows you and your companions to rest up to five times after the Legend has cleared all corruption from themself in a safe place.
For more information on Pathfinder: Wrath of the Righteous, check out Should you reveal the Light of Heaven sword to Sull in Pathfinder: Wrath of the Righteous? and How to unlock Devil Mythic Path in Pathfinder: Wrath of the Righteous on Pro Game Guides.