A young Starfleet soldier wounded on the moon J'Gal during the Klingon War, healed by Dr M'Benga and sent back to the front, whose death helps drive the doctor to take up arms.
Alder appears in the flashback scenes of the Strange New Worlds episode Under the Cloak of War, which return to the Starfleet field hospital on the moon J'Gal in 2257, at the height of the Klingon War. He is one of the stream of casualties treated by Joseph M'Benga and the newly arrived nurse Christine Chapel under constant bombardment and with almost no supplies.
M'Benga repairs the young man's injuries and, as the rules of the camp require, returns him to his unit as soon as he can stand. Alder goes back into the fighting and is killed soon afterwards.
His loss is one of the blows that lead M'Benga to inject the combat stimulant Protocol 12 and go after the Klingon commanders himself, and memories of patients like him lie behind the doctor's fury when the defector Dak'Rah visits the Enterprise years later.