What is the name of the Sith apprentice with a double-bladed lightsaber in Episode I?

The story behind the answer

In The Phantom Menace, the only Sith apprentice who wields a double-bladed lightsaber (saberstaff) is the horned Zabrak from Dathomir. Sidious is the secret Sith Master (Palpatine), not the apprentice; Count Dooku first appears in Episode II and uses a single, curved-hilt blade; Savage Opress is introduced later in The Clone Wars series, not in Episode I.

His acrobatic fighting style, performed by martial artist Ray Park, helped define the film’s climactic Duel of the Fates, where he kills Qui-Gon Jinn before being bisected by Obi-Wan Kenobi. His on-screen saberstaff popularized double-bladed lightsabers in Star Wars, expanding lightsaber choreography and influencing later stories.