"Shadow of Idea (2)" is episode 164 of the Berserk manga.
Mozgus and his two remaining disciples fly off toward the spirits, intending to distract or destroy them while the refugees erect a pillar on which to burn Casca. Like Mozgus, Azan feels the need to protect the helpless refugees, so he takes the Holy Iron Chain Knights to fight against the spirits as well.
Isidro has survived being thrown in the rubble of the Tower of Conviction and is desperately clinging to the edge of Albion's outer wall, more annoyed than injured. The commotion below him grows louder than ever, and when he glances down he sees Casca, now awake, being forcefully led through the crowd toward the pillar erected for her burning. Guts, who is at the very top of the Tower of Conviction, can also see Casca being abused, though he has no way of quickly getting down to her.
Suddenly, directly in front of him, Guts sees human-sized shapeless masses of spirits rise from the rubble. Despite being fully-formed, they don't attack Guts, who is holding the Dragon Slayer at the ready.
Guts spins around when he hears more spirits rising behind him, but these spirits are different; instead of maintaining a shapeless form, these spirits blend together into four distinct masses, which begin to mold themselves into specific shapes. The sight of them brings to mind the notion of the four angels, and Guts suddenly recognizes the shapes the spirits are forming: the silhouettes of Void, Conrad, Ubik and Slan of the God Hand. Moved by his wrath, he brings the Dragon Slayer down on Void's head, but since the latter is simply a mass of spirits, Void simply retakes his original form with no harm done.
Thinking back on the Skull Knight's warning from the few days before he arrived at Albion, Guts realizes that the members of the God Hand that stand before him are not in fact the real thing. They are hollow husks of themselves since they cannot take form on the mortal plane. What's more, Femto is nowhere to be seen among them. With these facts entrenched in his mind and the screams from the crowd below growing ever louder, Guts decides that saving Casca must take priority. As Casca is being tied to the tall wooden pillar, Guts charges through the shapeless spirits around him.