Commander Niall is a boss in Elden Ring. He is found in the Castle Sol, on The Mountaintop of the Giants. Like Commander O'neil, this boss wears heavy armor with a furry cloak and wields a standard as his main weapon. Unlike O'Neil, Niall has a bladed prosthetic leg as his other weapon. Niall will summon two ghostly Banished Knight spirits at the beginning; one with dual swords, and the other with a shield and sword. His attacks are either frost or lightning based.
Defeating Commander Niall will allow the player to get the second half of the secret Haligtree medallion