As it turns out, under the already perfect Three Demon Pill System, upgrading to the Four Demon Pill System is extremely difficult.
It's equivalent to creating a brand-new system.
No less challenging than installing an engine on a bicycle.
There are too many adjustments needed and too many problems occur. It's like playing whack-a-mole, to the point where Wang Wu almost had a mental breakdown.
At this moment, however, he felt grateful for the Evil Wind Bone Plague because he had endured even more desperate and dark times, so retreating now was not an option.
But the condensation of the fourth demon pill still made little progress, and Wang Wu spent a whole year struggling.
During this year, all the vitality he acquired was used to run the large model of the Four Demon Pill System.
Otherwise, by now he would have already upgraded the three demon pills, with his combined strength reaching the Fifth Grade, equivalent to a Little Demon King capable of ruling a mountain.
