|Hearts of Stone|
|Ancient effigies of discharged Gundead heroes animated by vengeful spirits.
Few Gundead can match the malice of these forgotten idols. Perhaps they are bound by a yet darker power...?
The Kill Pillars are a group of 4 enemies, each with their own health bars. However, unlike the Trigger Twins, they move as a group.
Their attacks consist of:
- A spinning volley of bullets which fill the arena. The player must stay close to the Kill Pillars and circle the boss to avoid taking damage. During this attack, the Kill Pillars will jump, sending out rings of bullets, which must be dodge rolled over. Both the rings and spinning arcs are jammed, dealing a full heart of damage.
- Jumping towards the player as a group, sending out bullets in all directions each time they land.
- Staying in the center of the arena while jumping more rapidly in succession, filling the screen with bullets.
- Lining up vertically on the left side of the screen and jumping to the right side, sending out bullets each time they land.
When one pillar is defeated, the others' eyes begin to glow.
When two pillars are defeated, the remaining pillars grow a third eye and the glow intensifies.
When only a single pillar remains, it will transform, heal itself up to full health again, and change its method of attack. It will continually jump and attempt to crush the player. When hitting the ground, it will release a large ring of bullets before attempting again to crush the player.
- Much like the Trigger Twins, if the player is able to kill the final 2 pillars at the same time, the final phase of the boss will be skipped entirely.
- Due to Boss Rush not instituting the normal boss damage cap, and Kill Pillars having four targets, Big Boy will refill on a single use that hits all four pillars. As such, it can be spammed against the Pillars in Boss Rush, allowing a near-instant kill on them.
- If you defeat all four Kill Pillars at once, it will not give you items, keys, Master Round, etc. that you would have received. It will also not revive a dead teammate in co-op mode.
- If the final pillar is killed while it is on the way down but before it has hit the ground, the pillar will still release a ring of bullets after the freeze-frame has ended.
- This is the only Hollow boss whose room can be entered from above.
- Explosive weapons can remove the spinning volley of bullets.
- The Kill Pillars are a reference to the Armos Knights from The Legend of Zelda series.
- The Kill Pillars' final form resembles Kaliber, the goddess of bullets. Statues of her can also be seen as decoration in the boss room of the Abbey of the True Gun when fighting the Old King. The Drunkard's lines after killing the boss appear to suggest that it was no other than Kaliber herself was in control of the statue: "Tell me... at the end. Did you see her? I can see in your eyes that you did. Know this: she is behind much of this."
- The Kill Pillars were originally known as the “Haunted Statues” in the pre-alpha with the tagline “Stone Spectres”.