What he saw with his eyes were the same pair of eyes that he saw back when he had just arrived in the first demon realm and fought the variant type demon.
Red blazing eyes that you could even feel the heat coming from those eyes. Or rather, came from the actual body of the variant type demon.
When the two eyes met, Blake didn't know what the variant type demon would do to him, but he wished with all his might that his face wouldn't be attacked since it was the only exposed area that wasn't protected by the dark earth armor.
And just imagining the intense heat that could even break his dark earth armor if it wasn't supplied by more nether hitting his face, Blake would literally lose his power to imagine anything anymore as his skull broke and his brain charred or melted by the intense heat that the variant type demon was able to emit from its body.