Soldier Ones are a breed of the Knights of the Underworld from Sonic and the Black Knight. They are the basic footsoldiers of their kind and the most versatile, each type varying between weapons, tactics, and roles. The name Soldier-One can refer to:
- Soldier-One (sword): The regular grunts and the main Soldier-One type.
- Soldier-One (spear): Variant that wield spears and shields.
- Soldier-One (axe): Variant that wield axes.
- Soldier-One (crossbow): Variant equipped with crossbows.