Admiral Gial Ackbar was a Mon Calamari native of the Star Wars Multiverse, and a well-known member of the Alliance to Restore the Republic.
He was perhaps most well-known for commanding the ship Home One in the Battle of Endor, the battle in which the Death Star II was destroyed. Ackbar was the first to note that it was a trap.
In some universes, he died peacefully in retirement, in others, he lived long enough for Leia Organa to convince him to join her Resistance against the First Order.
In some Universes, he was at one point a slave of Wilhuff Tarkin.