Tactical shooter Rainbow Six Siege has seen a resurgence of late. Thanks to a steady stream of updates to fix the game's core issues at launch coupled with consistent content drops, it's become one of the more popular multiplayer games around. Operation Grim Sky builds on this. The new downloadable content features new playable characters or operators as they're known; as well as a rework of its Hereford map. We tell you what you can expect when Operation Grim Sky is out.