Future Trunks returns to find the Future Warrior who had previously aided him in Age 783 in fighting off Dark Future Android 17 & Dark Future Android 18. As he goes to greet the Future Warrior he senses Villainous ModeFuture Cell, who Trunks is horrified to discover has managed to absorb Future 17 & Future 18 allowing him to reach his Perfect form in Trunks' timeline (a result of Towa's two stage plan to erase Future Trunks from existence). Joining forces with the mysterious Future Warrior, the two time travelers manage to overpower and kill Dark Future Perfect Cell restoring peace to Future Trunks' future timeline.
Having helped him twice, Future Trunks tries to get the Warrior to tell him who they are, but due to Future Trunks' role in the wish that summon the Future Warrior to Toki Toki City in Age 850 the Warrior responds with the cryptic answer "You'll know someday." before the Warrior returns to the Time Nest in Age 850.