Godstrike

Story Related. 

Duhm is the 5th boss you'll go up against and will start with a time of 4:50. After you defeat Mobus for Seeker , you'll unlock the Illusion and Thorned Shield abilities. You won't really be needing Illusion (it costs a lot and it's not really anything spectacular) so repeat the previous fight and equip the Beam, Overload and True Aim as your active abilities. For your passive abilities, it's really up to you and your play style but I recommend equipping Trinity, Spiked Boy, Reaper and Thorned Shield. Duhm has 3 phases:

Phase 1: The first phase is a basic bullet hell. You'll shoot him, he'll shoot you with many more bullets. Occasionally, he'll try and dash towards you but when he misses, he'll hit the wall and bounce a few times before letting out a ring of projectiles. He'll also turn into a sort of flying saucer and chase you around from time to time. When he does this, try and tuck away in a corner and he won't be able to reach you. 

Phase 2: Duhm will move to the back wall and will move left and right. He'll cycle through lasers and projectiles as his attacks but there will also be 2 additional enemies that will attack you. When Duhm stops on either side, the two additional enemies will hover on the left and right sides and slam down, releasing a ring of projectiles of their own which you'll need to dodge. 

Phase 3: Duhm will be back in the open and will basically combine Phases 1 and 2, with 2 being the additional enemies. His attacks will be quicker and more aggressive so just make sure you're constantly moving to avoid everything being thrown at you. 

After you've defeated him, the trophy will unlock. If you need a visual reference for this fight, please see the video provided under Guardian . This fight starts at 12:41.