At another location deep within the Underground Palace.
An oval-shaped gate of light appeared out of nowhere. Dense spiritual energy wafted from within it, carrying a rhythm that inspired awe from the depths of one's heart.
The moment he approached, Li Yun's mind shook.
Immortal Rhythm!
Having entered the Royal Dungeon of the Mysterious Moon Kingdom and joined forces with Zhao Fangqun to slay an Immortal-level Devil Race Pro Demon Lord, he was already no stranger to this kind of rhythm.
What shocked him was that the Immortal Rhythm emanating through this Light Curtain was far stronger than the one emitted by the Royal Dungeon of the Mysterious Moon Kingdom—stronger by far.
The instant he sensed this Immortal Rhythm, the system was triggered.
Moreover, this trigger was clearly different from before. This time, the system prompt had actually made a clear distinction between different Immortal Rhythms.
Observing Human Immortal Rhythm, Human Immortal Level Cognition +1...
Observing Earth Immortal Rhythm, Earth Immortal Level Cognition +1...
Damn?
Had the system upgraded?
Li Yun was stunned on the spot.
"Young Master Li, what is it?"
"What has surprised you so much?"
Ye Shenfeng at his side noticed that something was off about Li Yun's expression.
Li Yun was somewhat flustered, but he knew this was not the time to investigate. He quickly smiled and covered it up. "I was startled. This Ancient Battlefield Secret Realm really is extraordinary... We haven't even entered yet, but the spiritual energy already feels so abundant. And it seems to contain a rich... Immortal Rhythm?"
Ye Shenfeng's expression changed. "Young Master Li knows about Immortal Rhythm too?"
"Cough, cough..."
Li Yun gave a dry laugh. "I know a little, but not in much detail. Young Master Ye, your clan has deep foundations. Why not explain it to me