Tom Clancy's Rainbow Six

Tom Clancy's Rainbow Six was made by Red Storm Entertainment, a studio co-founded by Tom Clancy himself, and, in 1998, brought a strong emphasis on planning to the tactical shooter genre: before each mission the player assembled a team, chose loadouts and plotted routes for separate squads, while combat itself was unforgiving - a single hit often meant a soldier's death, and an operative killed or badly wounded could be lost permanently across the rest of the campaign. Based on Tom Clancy's novel, it leaned on a level of realism that stood out amid the run-and-gun shooters of the time.

The sequels Rogue Spear and Raven Shield refined the tactical formula further, adding more sophisticated AI for both teammates and enemies and expanding mission-planning options; both also received several expansion packs and were popular on the competitive PC scene of the era. After Ubisoft acquired Red Storm Entertainment, the series became part of a wider roster of Tom Clancy properties alongside Ghost Recon and Splinter Cell. Over time, however, it began drifting toward a more accessible, action-oriented style aimed at consoles as well - Lockdown was noticeably more linear and less dependent on the preparation phase, which did not sit well with some longtime fans.

A more radical shift came with Vegas and Vegas 2, which moved the action to Las Vegas and replaced strict tactics with a cover system: taking cover switched the game from third-person to a first-person aiming view, and the games also introduced character customisation. This approach was well received by both critics and players and briefly returned the series to the mainstream spotlight, while the subsequently planned Patriots was eventually cancelled after a long and troubled development.

The series was ultimately defined by Rainbow Six Siege in 2015, which returned to its tactical roots but built them purely around competitive five-versus-five multiplayer, destructible environments and operators with unique abilities on both the attacking and defending sides. After a modest launch, years of steadily added content and tournaments such as the Six Invitational turned Siege into one of the most successful and longest-running esports titles, showing that the series could keep reinventing itself without losing its core identity.