About
In the distant future, Sailor Chaos emerges from the Galaxy Cauldron and is the source of catastrophe. Sailor Cosmos tries to stop the constant death and destruction but is unable to defeat her. Eventually, she loses all hope of stopping Sailor Chaos and reversing the damage inflicted. She would think of her distant past when she challenged Chaos at the Galaxy Cauldron and thought if she had destroyed them both back then the carnage could have been avoided. That regret eventually grew into action as she returned to the past with the goal of guiding her younger self to make that alternate decision while disguised as a young girl: Chibi Chibi.
Eventually, Sailor Chibi Chibi stands alongside Eternal Sailor Moon facing down Chaos and the Galaxy Cauldron but rather than convincing Usagi to destroy the Cauldron as intended, Usagi convinces her the action she took so long ago was the correct one. Usagi tells her not give up hope for her future and in tears, Chibi Chibi agrees and reveals her true form telling Usagi they won't lose. She watches on as Eternal Sailor Moon makes the same decision she had - Usagi gathers the power of all Sailor Crystals inside and outside of the Galaxy Cauldron and attempts to embrace Chaos and save her friends and dies in the process. This creates the Lambda Power of the Cosmos Crystal which regenerates the galaxy, including Usagi herself and her friends, and sees Chaos dissolve back into the depths of the Galaxy Cauldron.
The Sailor Quartet find Sailor Cosmos watching near the Cauldron and she tells them her story and what Eternal Sailor Moon accomplished. Sailor Ceres calls Sailor Cosmos "Sailor Moon's Ultimate Form" but Sailor Cosmos will not hear it. She does not compare herself favorably to Sailor Moon, believing she is not worthy of the title "Sailor Cosmos" or the Cosmos Crystal she wields. Instead she calls Sailor Moon the "True Sailor Cosmos" as it was she performed the courageous feat at the Galaxy Cauldron that saved the galaxy and united Sailor Crystals from all over to create the Cosmos Crystal she wields in the first place. She doubts herself but hopes she can have the courage to become worthy of the title. When she is finished speaking to the Sailor Quartet, Sailor Cosmos sends them back to the 30th Century to protect their princess, Sailor Chibi Moon.
Afterwards, she returns to her own time with renewed hope and inspiration from Eternal Sailor Moon's actions. The result of her next meeting with Sailor Chaos or the ultimate fate of the universe is left unknown.