3DM is a Chinese video game warez group – a group of individuals specialized in cracking the digital rights management (DRM) applied to commercial PC video games. It is "one of the world's biggest" such groups, according to Kotaku.
Their founder and leader is reported to be a woman using the pseudonym "Bird Sister" (simplified Chinese: 宿菲菲; pinyin: Sù Fēifēi). Unusual for piracy groups, 3DM's members have public profiles on the social network Sina Weibo, and use a blog to inform the public about their activities.
3DM made gaming media headlines in January 2016 when Bird Sister wrote that she anticipated that in two years no more cracked games would be available, owing to new anti-tampering technology by Denuvo then beginning to be widely applied. The group also announced that it would quit cracking games for a year, and later claimed it had defeated Denuvo's technology.