The black jewel was only as big as an egg, yet it was pitch black with a remnant of lightning channeling on the surface, containing enormous thunderous power inside.
Located in the middle of the Sky Thunder Array.Sky Thunder Jewel, that's another spiritual device, and it's even an upper-grade one with the capability of controlling thunder.
Sky Thunder Jewel was a Dharma artifact, which could summon and store lightning. Qingfeng Li acquired it with the help of the Dark Night Emperor.
Obtain in chapter 879.