Zwei II is an action RPG that serves as a direct sequel to Zwei!! but stars a new cast of characters and trades the previous game's 2D over-head perspective for a fully polygonal presentation. The title was developed in 2008 by Nihon Falcom for Windows and was the last game created exclusively for the PC by the company before they shifted focus to console and handheld development. Almost a decade after its Japanese release, XSEED published Zwei II in the West under the name Zwei: The Ilvard Insurrection on Halloween of 2017. The English release used a heavily edited script from an unreleased fan translation created by the Birds of a Feather group and also contained an English dub with additional recorded lines that were not voiced in the original Japanese.
- According to a 2017 interview with App Bank, Zwei II's director and president of Falcom, Toshihiro Kondo, revealed that the game was initially going to be the seventh mainline entry in the Ys franchise when development first began. However, as development continued, the tone and style of the game started to depart from the Ys series so it was decided that the game should change to be a sequel to Zwei in order to give the team more freedom to develop their ideas. A true Ys Seven would later be released in 2009 for the PlayStation Portable.