That were introduced in Japan's PSO2 with Episode 6 from Nfkjasfas's blog

This beta phase will have a limited number of applicants who will enroll at a first come, first served basis, so make sure you sign up fast once the enrollment begins meseta pso2! Final Battle: Space-time Interstice is a new Ultimate Quest that's players challenge that the Primordial Darkness. Only senior-ranking Arks (those above level 90 on both Main and Sub -- Class) should try this assignment, as it is to be done solo.

Fire has broken out at the City Area of this ARKS Ship, and all available operatives must respond, as a few citizens remain unaccounted for at the tumult. A rescue effort has been mounted, and also the SWIRLING INFERNO ON THE ARKS SHIP has to be extinguished to prevent additional damage or loss of life.

Additionally, Officer Cofy will provide you with Rescue Guns; engineered to be more effective against FLAMING DETRITUS, which should be suppressed to ensure the safety of citizens that are trapped. It's likely that there are quite a few citizens in need of aid, so this Urgent Quest will be repeatable. Falspawn and other enemies of ARKS creep amongst the ruins to harass the survivors and further fan the flames. Destroy them and you may find they have picked up a thing or two amongst the wreckage.

This quest is available on Ultra Hard, though only to veteran ARKS that have achieved Level 85 on either the Main and Sub Class buy Phantasy Star Online 2 Meseta. You'll have failed this quest should you exceed the time limitation of 60 minutes.