Shao Kahn
Despite not being playable nor appearing in "Mortal Kombat 11" (2019), Quan Chi was referenced by most of the characters. During the "Aftermath" DLC in particular, Sindel reveals he killed her for apparently distracting Shao Kahn, staged her murder to appear as if she committed suicide, and used her soul to prevent Shao Kahn from invading Earthrealm until the time was right.