Berserker Lords are Berserker Knights that have been severely exposed to Phazon. These Pirates are much more resilient and have Phazite plating for shielding. Because of this, they can be easily killed using the Nova Beam in conjunction with the X-Ray Visor. They have only been seen in Metroid Prime 3: Corruption.
It appears to be a continuation of the research experiments conducted by the Space Pirates almost three years prior. Those experiments results were the Elite Pirate and Omega Pirate, with the Omega Pirate being the Berserker Lord's equivalent.
- "Berserker Lords are highly resistant to damage. Their shoulders are the only unprotected area vulnerable to standard weapon fire. Their main defense lies in their head-mounted Phazite plating, which can only be destroyed by the projectiles it fires. Berserker Lords are a desperate measure, designed to exploit Phazon as much as possible. The few Berserker Knights that survive the highest level of corruption are promoted to Lord status. Lords are distinguished by their ornate Phazite plating and the Phazon reserves they carry on their backs." — Logbook "Berserker Lord" (Metroid Prime 3: Corruption)