History
She was the Empress of the Shi'ar Empire. On her throneworld began a planetary war, and her forces failed. Lilandra fled to Earth, looking for help to regain her throne.
Negotiations between humans and Shi'ar were held in Xavier Institute, with several of the Earth's mightiest heroes under one roof.
But Lilandra was betrayed by her own daughter Alanna, who usurped command and killed Lilandra, Charles and all who were in Institute. Paving the way for conquest of the planet with the backbone of the superhuman community having been nullified.