Cortana is the artificial intelligence who accompanies Master Chief throughout Microsoft's Halo series, first appearing as a holographic companion and tactical guide in the early games before becoming widely known as the name of Microsoft's digital assistant. Her calm, distinctive voice made her one of gaming's most recognisable AI characters, and short clips of her dialogue have circulated widely on soundboards, in fan edits and in reaction videos. Fans still use them to evoke Halo, futuristic technology and the series' long-running human-AI partnership.