Which Assassin's Creed game introduced the Animus's modern successor, the Helix?

Assassin's Creed Unity introduced the Helix, the modern successor to the Animus.

The Helix is a consumer-facing entertainment system connected to Abstergo's efforts to commercialize genetic memories. In Unity's modern-day framing, the player is invited to experience the French Revolution through Helix rather than following a named modern protagonist in the same way as earlier entries. The Assassin initiative then attempts to recruit the player.

The Helix is not simply another historical device. The Animus is the technology used to access genetic memories, while Helix is presented as a newer commercial platform based on that concept. Assassin's Creed Syndicate continues this style of modern-day framing and also uses Helix-related material.

Unity's historical story follows Arno Dorian in Paris during the French Revolution. The game was released in 2014 and was developed for PlayStation 4, Xbox One, and Windows. Earlier games, including Assassin's Creed III and Black Flag, centered their modern-day plots more directly on Desmond Miles and the Animus.