PHANTASY STAR ONLINE 2: EPISODE ORACLE

Based on the Phantasy Star Online 2 MMORPG published by SEGA. It covers the first three episodes of the original game and an original story. The game storyline follows members of a planetary exploration organization ARKS, based on the colony fleet Oracle that's searching for a habitable planet for its population. The members of ARKS defend Oracle and other planets from monsters called Darkers, which are under the control of the villainous Dark Falzes. — Description from AniList community (anilist.co).