List of Hard Mode Last Boss Columi Drops

Esseles - Columi Bracers
Taral V - Columi Gloves
Maelstrom Prison - Columi Boots
Directive 7 - Columi Legs
Battle of Ilum - Columi Offhand
False Emperor - Columi Chest
Kaon under Siege - Columi Head

Please note that even though a piece is guaranteed to drop, the class its for is (you've guessed it) random! Good luck getting them cuz god knows how horrible it feels to go through the FP and find a gear that doesn't fit for any of the party members.

Detailed Version

False Emperor
Jindo Krey: Tionese gloves
HK-47: Tionese Mainhand
Bonus: Sith Entity: Tionese implants
Darth Malgus: Columi Chest

Directive 7
Interrogator: Tionese wrists (bracers)
Bulwark: Energized chest
Bonus: Replicator: Relic
Mentor: Columi pants

Ilum
Velasu Graege & Drinda-Zel: Tionese wrists (bracers)
Krel Thak: Energized head
Bonus: Guid Patriach: Tionese ear
Darth Serevin: Columi Offhand

Kaon Under Siege
Defend vs Zombies encounter: Xenotech Gloves
Rakghoul Behemoth: Tionese grade mainhand with Q56 color crystal
Bonus: KR-82 Expulser: Columi head
Commander Lk’Graagth: Columi head