The Pyke Syndicate Assassin is a fast and agile boss who relies on stealth and melee attacks. This encounter often takes place in an environment with many obstacles and cover points, which the Assassin will exploit. The fight has three distinct phases.
Phase 1: Stealth Ambush
The Assassin will frequently enter stealth, disappearing from your sight. Use Nix's 'Scan' ability to highlight his position, even when cloaked. He will attempt to close the distance for a powerful melee strike. Dodge roll away from his attacks and counter with quick blaster shots. Some sources suggest that 'Sonic Emitters' can force him out of stealth, making him vulnerable for a short period.
Phase 2: Dual Blasters
After taking significant damage, the Assassin will abandon stealth more frequently and switch to dual blasters, firing rapidly. Maintain distance and use cover. This phase requires precise aiming to hit his head, which is his primary weak point. Nix can be used to retrieve health packs or distract him, giving you a moment to reload or heal. Be wary of his quick dashes.
Phase 3: Desperate Measures
In his final phase, the Assassin becomes more aggressive, combining melee charges with blaster fire. He might also deploy smoke grenades to obscure your vision. Use your own smoke grenades to create cover or escape. Focus all your remaining firepower on him. If you have any 'Stim Packs', now is the time to use them for a damage boost. Defeating him often yields a unique melee weapon and a valuable data chip.