When the choice comes, sacrifice yourself to give mankind another chance.
A Better World
When the choice comes, choose to flee to the Starcity and create new mankind.
What’s Reality Anyway?
To get this ending, you have to start back at Black Light, Part II, so make a save right after this mission!!
Start by making sure that the quest Secrets is completed. You got it back at the beginning when finding the key of Yero. If not, complete it by visiting Yero’s Tower (south of the Sun Temple entrance) and obtaining the Dreamflower Recipe at the end.
Then during the quest, A Drop in the Ocean collects 2 dream flowers before talking to Yuslan in an alternate reality. Go back through the portal, talk to Yuslan, and give him the Dreamflower. He will brew a potion for you in two days, which unlocks:
Keep the Dream flowers. Make sure you’ve completed Dark Chambers of our Minds from the “Arena and Rhalâta questline” because you need to use the Dreamflower in the Substance Decomposer in The Father’s room. This will brew a non-purified Dreamflower potion.
Ingredients needed: Dreamflower, Human Heart, 2 Glimmerdust, Grand Soul Gem (Filled)
Drink it, then once you get to the mission, Fleshless choose to sacrifice yourself, and should you get the final and best (in my opinion) ending!!