The flame of life force burned hot in Greed-possessed Meng Hao's eyes, as if a sea of fire existed therein. However, that sea of flames was being reduced as the fourth Nirvana Fruit in his forehead sucked it away.
That Nirvana Fruit seemed like a bottomless pit!
When Meng Hao had absorbed the fourth Nirvana Fruit before, he had only been able to endure for a brief moment before stopping. The Nirvana Fruit had emerged from him of its own volition; had it not, he would have been sucked dry.
Furthermore, every time he used it resulted in a period of weakness afterward, a time that had to be spent in recovery. That was the obstacle preventing him from stepping into the Ancient Realm; if he could not fully absorb that fourth Nirvana Fruit, then he would never be able to do so.