Blockner is a secret boss found in the Black Powder Mine. He is Manuel's old partner from when they entered the Gungeon seeking the Gun that Can Kill The Past. Blockner betrayed Manuel and killed him, transforming him into a ghost. In order to get to Blockner, the player must find the secret room in the Hall of Knowledge and pick up Old Knight's Helm and Old Knight's Shield. After defeating Ser Manuel, if spoken to, he will inform the player of Blockner. Blockner will then appear in the Black Powder Mine, along with two Gun Nuts as bodyguards.
If Blockner is defeated for the first time (not as a ghost) and is defeated flawlessly, he will drop a Master Round for that chamber. If the main boss of the chamber is also defeated flawlessly, it will not drop another master round. It is currently unknown if the same applies in reverse.
Once defeated, Blockner's ghost can appear in the Gungeon as a mini-boss, similar to the Shadow Magician. Upon death, he will drop several pickups.
Blockner spawns with two Gun Nuts aiding him. He has a few attacks:
- Slowly walks towards the player, rapidly firing bullets.
- Fires a wide spread of bullets like a Gun Nut, along with four smaller arrows of bullets.
- Fires bullets in all directions in a shield shape while firing a spinning cross shape of bullets toward the player.
After defeating him for the first time, Blockner's ghost can appear as a mini boss in later runs. As a mini boss, his fight mostly stays the same with a few differences.
Note that Blockner's ghost will either spawn in an oval-shaped arena, similar to the Shadow Magician, or in his own special shield-shaped arena. Seeing either of these shapes on the map of the floor after the floor is revealed by a Map, the Cartographer's Ring or the Gungeon Blueprint can help the player prepare for a fight against Blockner's ghost.
- Blockner no longer spawns alongside two Gun Nuts, leaving him alone against the player.
- Alongside all his attacks, he gains a new attack in which he summons five shield shaped bullets. Four of them quickly move to each corner of the room while one stays around Blockner, they don't move and later on disappear.
- When he fires bullets in all directions taking the shape of a shield, he fires two spinning cross bullets at the player.
In the Breach:
- "I guess I should thank you for taking pity on Manny. But I won't."
- "What's a bit of revenge killing between friends?"
- "Death doesn't seem to mean a whole lot here, though."
- "Trapped here for all of eternity."
- "I guess this isn't so different from before, when I was alive but trapped here for all of eternity."
- "The other dungeons me and Manny used to loot never had any guns. It was always sharp metal."
- "Maybe now I can finally learn to roll."
- "I decided to go back in for some action. Sorry if I gave you trouble." (after defeating Blockner's ghost)
- You can encounter his ghost as a miniboss on the same run you kill him on. As his ghost form is a separate entity from his living form, whether or not he was jammed before will not affect his state later in the run.
- Ser Manuel has a line where he mentions the moments after being killed by Blockner. He says he was inside a chest and from that moment on, he was a ghost. This might be a reference to coop chests that revive players, meaning that the dead player becomes a ghost after their death, and the chest has to be opened by their ally to come back to the physical plane. Since Manuel had to get out by himself, he remains as a ghost. The reasons for Blockner being a ghost and not respawning are unknown.
- His name being "Blockner" is likely a pun on his affinity with shields, as a shield is used to *block* blows.
- If properly timed and the player is wielding Casey, Blockner's ghost can be killed almost immediately by his own shield attack. The player must hit him with a fully charged strike immediately as his shields begin to divide across the room; doing so will parry most of them into him before they have a chance to disperse. The same thing can happen when using the Finished Gun.
- He is very skeptical about Manuel's dodge roll technique, believing that it shouldn't work and using shields as an alternative way of defense. This could be a reference to the Dark Souls video game series.