Since nothing came to mind temporarily, Merka decided not to dwell on it any longer.

After all, the tasks at hand remained unchanged.

"Last time I encountered a fork in the road here..."

"Let's go up and take a look."

Merka arrived at the staircase. He clumsily controlled the slender limbs of the Harbinger and made his way up the swaying stairs.

After a short while, he found himself in front of a large door.

The door faced the ground, seamlessly connecting with the surrounding ceiling.

Merka looked up, hands resting on the door, carefully inspecting it. He noticed the corner of the door bore the words "Emergency Isolation Door" in English.

Merka could probably guess that the passageway between the first and second floor had been emergency closed for some whimsical reason after the initial breach of the smoke-free zone.

Running his hand over the material of the door, Merka understood it well.

He suddenly raised his hand and punched the center of the door.

But all that was left was a white mark.

"Even though this is a wall made by Rongmu."

"But based on the power of the Harbinger, it shouldn't be unable to break through Rongmu..."

Merka felt a bit disheartened, but he did not give up.

"Well then, what about Power Angel, known for its strength?"

Merka reached out to the location of the backdrop on his chest and softly uttered the name of Power Angel.

"Power Angel, are you there?"

Behind Merka, a dark tide surged out, like sewage bursting through a manhole cover during a storm.

A Power Angel, entwined by numerous tentacles, its body expanding by a full circle, crawled out of the dark tide, resembling a darkened version.

With its eerie, menacing appearance, rows of shark-like fangs, and its limbs and torso wrapped in sinews, the current Power Angel seemed stronger than before.

Merka hesitated for a moment, then faced Power Angel and pointed to the wall above.

"Can you destroy this wall?"

As soon as Merka finished speaking, Power Angel viciously raised its fist and smashed it against the wall above.

A terrifying roar exploded in Merka's ears.

The dreadful sound, as if a crane had forcefully extracted the foundation of a tall building from the ground, made Merka's heart tremble incessantly.

Merka almost thought the whole building was going to collapse.

Finally, the shaking subsided.

Brushing away the acrid smoke and dust, Merka coughed lightly and squinted his eyes as he looked at the ceiling, only to find a small dent in the door above.

"This is a joke... Even Rongmu shouldn't be this tough..."

"Wait, this is..."

Using his magical vision, Merka carefully observed and discovered that from the small dent emerged several thin tentacles. In no time, these small tentacles completely repaired the dent.

The repaired door still looked as good as new, completely undamaged, as if freshly manufactured.

"So that's how it is... It brainwashed an angel in the laboratory, made it believe it was Rongmu, and then placed it here as a door."

"This kind of door is not only indestructible but also self-repairing..."

"Such usage is beyond imagination, truly absurd."

Merka sighed as he touched the wall in front of him.

"If only I knew how to use aside... Maybe then I could manipulate the memories of this angel and turn it into something else."

"But wait, am I about to turn into the Harbinger?"

"Then I should become an angel as well... or perhaps, a half-angel, like Turing!"

"Conscious angels should have some essence of aside and backdrop, right?"

Merka clenched his fist, recalling the feeling of using the backdrop machine and aside machine in his mind, continuously gesturing spell-casting movements and uttering incantations.

However, he found no response in the end.

"No, it's not working."

"I should go back to the hall first..."

"I'll have to find Turing."

"If I find Turing, all these issues can be resolved effortlessly."