Ace was astounded as Ascension or Abyssal Grade-9, in both the Abyss of Wandering Souls and Mortal Ascension Heaven, was the highest threshold of treasures. Treasures of that caliber were peerless, war-ending devices, things that could warp fate.
Looking at the door, Ace's expression turned solemn as there was no brute-force solution. He could imagine delivering the same punch that cracked the crystalline wall—and the impact would be an insult to the door.
Even if his physical body could be empowered through treasures, he didn't possess the cultivation level required to force such a thing.
To directly break or blast this seal would require an Ascension Lord stature or an Ascension Grade-7 universal physique.
Furthermore, his Avatar of Holy Twilight upgraded in tandem to use the Twilight Traverse, so the shared resonance could meet the door's requirement, which also required time he did not have.
