On the battlefield, if they could not speak or communicate, they would become deaf and mute. That was manageable for a single team, but if several teams had to coordinate in battle, it would become a joke.
The location for upgrading lightning forbidden spells was inside the Lightning Tower in the central area of Sky City. Lu Yang brought Mu Yu and the other ten into the Lightning Tower. When they reached the twenty-third floor, they saw an earth-elemental creature whose entire body looked like lightning in the main hall.
Thunder Elemental Spirit (God) Level: 200 Health: ?/?
"It's actually a god-level creature." Yinghun Bu Mie exclaimed.
Lu Yang secretly smiled. Once they killed this Thunder Elemental Spirit, they would obtain half of the required items for the Heart of Thor's Level 10 class advancement.
The Thunder Elemental Spirit stood around five meters tall. Looking at Mu Yu, Yinghun Bu Mie, and the others, he said in a dignified voice, "Young humans, I can sense the fluctuations of lightning elemental gems from you. Are you willing to give those gems to me?"
Mu Yu looked at Lu Yang. Lu Yang gestured for her to agree, so Mu Yu took out a gem, handed it to the Thunder Elemental Spirit, and said, "All right, this is for you."
The Thunder Elemental Spirit gave a satisfied hum. A flash of light passed, and the gem entered his body. He sighed and said, "It has been a long time since I last replenished my energy. This has allowed me to feel power once more. In exchange, I will upgrade your lightning forbidden spell, Electromagnetic Storm, into Super Electromagnetic Storm."
A ray of lightning entered Mu Yu's body. The next second, her forbidden spell Electromagnetic Storm became Super Electromagnetic Storm.
``` "Super