Complex sentence: Having fully awakened the Black Blood with knowledge of Medusa's plan, Crona departs to the moon where Crona absorbs Asura and is confronted by Maka and her friends until Asura resurfaces and takes over Crona's body.
Split into simpler sentences: Having fully awakened the Black Blood with knowledge of Medusa's plan, Crona departs to the moon to Asura. Once fulfilling that objective, Crona is confronted by Maka and her friends until before losing control with Asura taking over Crona's body.