- Adaptation Distillation: The OVA version of Ys II: Ancient Ys Vanished – The Final Chapter tightens things up considerably and adds a few interesting elements like a twist on the in-game reliance on magic.
- Adaptational Early Appearance:
- In canon, Dalles's first appearance is Ys II. Here, he appears during the events adapted from Ys I.
- In Ys I, Dark Fact never appeared until Adol reached his boss room. Here, he gets scenes starting after Adol defeats Jenocres.
- Dogi and Goban also appear earlier when they save Adol after he was washed ashore.
- Adaptational Late Appearance: In Ys I, Jenocres was the very first boss Adol faced. In the ova, Jenocres appears after Adol escorts Feena to Jevah's home.
- Adapted Out: Zava makes no appearance in the OVA whatsoever.
- And the Adventure Continues: After Darm's destruction, Adol sails off to his next adventure. Too bad future events never got adapted for this continuity with an Ys IV OVA never getting made despite Falcom's efforts.
- Call-Forward: Dogi talks about his homeland Felghana, which sets the stage for events to come for the events of the third game. However, no further ovas in this series was made.
- Cool Horse: Adol rides a horse when traveling from Zeptic to Minea. He, Goban, and Dogi later ride them in search of Volume Messa.
- Dies Differently in Adaptation:
- In the first game, Jenocres falls in battle against Adol in the Shrine. Here, Adol kills him in Minea after the crystal weakens him severely.
- In the games, Dalles dies for good when Adol cuts him down. In the anime, Darm kills him be tearing him to shreds.
- Early Adaptation Weirdness:
- Jenocres is portrayed as a human crony who worked for Dalles. Ys Origin establishes that he is a pure demon.
- Several of the boss demons encountered in the anime were shown to be capable of speech, this is never retained in Ys Origin.
- Power Ballad: "Endless History", the ending credits theme from the Ys anime, which is also a vocal remix of "The Morning Glow" from the first game.
Anime / Ys