Destiny Ascension

The Destiny Ascension is an asari dreadnought and flagship of the Citadel Fleet. It is a starship of stunning power; according to a volus visitor, it has almost as much firepower as the rest of the asari fleet combined. The Ascension is currently commanded by the asari Matriarch Lidanya.

Specifications
The Ascension is four times the size of the largest human ship, and boasts a crew of nearly 5,000. It is considered to be the most formidable warship in the galaxy, with heavy kinetic barriers and powerful weaponry. The Ascension is most likely the Citadel Fleet's largest ship, as no other Fleet vessels are seen that match it in size.

The Ascension can be seen passing the windows on the Wards while people gather around to watch. A nearby volus can be heard talking excitedly about his recent tour of the Ascension: though he was aboard for six hours, he only saw 10% of the ship, for the vessel was simply far too large to tour completely.

Mass Effect
When the geth fleet, led by Sovereign, attacks the Citadel, the Council is evacuated to the Destiny Ascension as per standard emergency procedures. Since the dreadnought is not designed for close combat, it fails to escape and becomes heavily damaged. The arrival of the Alliance Fleet is the Ascension's only hope of survival.

Shepard has three choices: command the Alliance fleet to save the Destiny Ascension (at the cost of many human lives and potential reinforcements), to concentrate the attack upon Sovereign (leaving the Destiny Ascension to be destroyed by the geth fleet), or to allow the Council to die. The first option results in humanity gaining a seat on the Council. If Paragon, the second and third options results in humanity leading a new Council in cooperation with the other races. If Renegade, they result in humanity creating a new all-human council.

Mass Effect 2
If the Alliance Fleet saves the Destiny Ascension, the vessel undergoes a twenty-colony victory cruise, completed in 2185. If the Destiny Ascension is destroyed at the Battle of the Citadel, a news report states that the asari have ceded the share of responsibility for Citadel defense to the turians.

Trivia

 * Matriarch Lidanya may be the asari aboard the Destiny Ascension who is glimpsed during the assault on the Citadel. When she realizes the Citadel's systems are not responding to commands for the station to close, she gives the order to evacuate the Council.
 * In Mass Effect 2, Shepard is able to purchase a model of the Ascension for the Captain's Cabin on the Normandy.