The Keyblade wielded by Xehanort is called No Name.
No Name is an ancient Keyblade associated with Master Xehanort and is also known as the Gazing Eye. Its distinctive eye motif connects it to the Master of Masters and to the Keyblade’s role in observing events across the Kingdom Hearts mythos.
Xehanort uses No Name prominently in Kingdom Hearts: Birth by Sleep, where he battles Terra, Ventus, and Aqua and uses the Keyblade in his plan to summon Kingdom Hearts. The weapon remains tied to his identity across later revelations about his incarnations and apprentices.
The wording can cause a mix-up because No Name is strongly associated with Xehanort’s use of darkness, but it is not simply a “darkness-only” Keyblade. Way to the Dawn is chiefly associated with Riku, Oblivion with Sora, and Kingdom Key is Sora’s signature weapon.