Little Bai?

Zhu Youji's initial thought was a pyramid.

Having a perpetual energy pyramid, if taken out directly, could instantly overcome all obstacles! In this world below, where only grandmasters exist, this belongs to the category of super-nuclear-level weapons, capable of effortlessly sweeping away everything.

But this notion quickly vanished from Zhu Youji's mind. The reason was simple. After experiencing several bugs in the system previously, it had become smarter.

It would now verify whether the item to be exchanged meets the standards. If it doesn't, it won't allow the exchange.

In this scenario, exchanging the pyramid directly would undoubtedly be like offering oneself up to the system for exploitation.

Such an obvious loophole couldn't possibly be exploited.

As a second option, what Zhu Youji admired the most was the impregnable anti-aircraft formation, touted as undefeated.