Adding co-op to Assassin's Creed was "complicated"

Bringing co-op play to the Assassin's Creed series took years to do because it was so "complicated".

That's according to senior producer Vincent Pontbriand, who claimed the Assassin's Creed engine required years of rebuilding to include the feature.

Assassin's Creed Unity will be the first game in the series to have co-op play, as previously multiplayer was just a competitive mode.

"Because it's very complicated to do," he told CVG. "Assassin's Creed was always a single-player game to begin with. It took us three games to introduce PvP [player versus player, which was introduced in Brotherhood].

"[AC Brotherhood's multiplayer] was in the same universe but you were playing as a Templar avatar in a very separate game mode. In Unity, we set out to unify all these game modes into a single experience.

"That's when we decided that co-op should be the next main focus, but in order to do that we had to rebuild all of our systems to allow them to be replicated over a network and working online.

"It took years of development to reproduce and redraft all of our sandbox features for a shared online experience."

Assassin's Creed Unity arrives 28 October for PS4, Xbox One and PC.