Ubisoft has been developing Assassin’s Creed games for nearly a decade now, with the series spanning across two console generations. A lot has changed since those early days – those crowds of several dozen NPCs have certainly grown – but some aspects are the same. Ubisoft’s technical engineers are continually pushing themselves to see what’s possible, all the while trying to wrap their minds around hardware that may not even have final specs. I spoke with technical director James Therien, who’s been on the series since the first entry, to learn about his Assassin’s Creed experiences.

Therien has been working on games for a while now, or, as he puts it, “I’ve been in the game industry for longer than I’d care to remember.” He did programming work for titles including Star Trek: Bridge Commander, Secret Weapons Over Normandy, and Medal of Honor: European Assault. He was working at EA’s Montreal studio when companies were starting to anticipate Sony and Microsoft’s post-Xbox and PlayStation 2 plans. At the time, Therien says that EA seemed unprepared. “They sort of at that time didn’t know what to do with the new generation,” he said. “I could see that the AC team really had a clear idea of where they were going.”

“I joined Ubisoft in 2005, and actually I started right on Assassin’s Creed 1,” Therien says. “That was the big time of the old-gen transition, and it was really exciting because Assassin’s Creed was really an amazing proposition. They sold me at the pitch, just with videos and what they wanted to do, like the open world and the interaction with the environment and the parkour – it was already in the concept video back then, and I said I want to work on this game.”

Therien started working as a graphics programmer, but he says the studio had that aspect of development well in hand. He shifted his focus over to A.I., particularly in the way that players interacted with crowds. When the game shipped in late 2007, interacting with that many NPCs was a highlight. He and the team started much smaller, however. “At the very beginning it was 10 NPCs, maybe 15 NPCs, and I remember Patrice [Désilets, the designer of the first two games] telling me, ‘Imagine if we could have 40 NPCs.’” Looking at the crowd density of Assassin’s Creed Unity – Ubisoft says up to 12,000 characters can appear on screen at a time – that target number seems quaint.