What could be? Lu Zhi can be Keira? Is it a different fight?
The last boss in the Memory Cloud encounter is either Lu Zhi or Keaira (depending AFAIK on whom the raid leader chose before entering the Emperor's room for the first time). They do have different abilities etc. Think of it as a similar situation to the Keeper of Artifacts, except that here in the Memory Cloud they also have different names. (In fact you might simply refer to this encounter as Memory Cloud in your list, since that seems to be Funcom's official name for it.)