Indeed, Guan Heng had a head of jet-black, naturally curly hair. At just over six feet tall, he looked quite average next to the imposing figure of Lei Shen. Standing beside him, Guan Heng seemed like a mere sprout compared to a towering tree!,Iron Man suddenly chuckled dryly, speaking to himself: "My father participated in the rebirth plan back then, keeping a tube of the most original super serum. I don't know what side effects it has. I've always kept it as a treasured relic from him, dear Guan..." Tony's face instantly darkened, revealing a sinister smile, "For world peace, for enhancing your abilities, I'll have to burden you a little! Thor, hold him tight! I'm going to get started!",It's unclear if it was due to the Super Serum, but Guan Heng's progress was abnormally rapid. His physique grew increasingly strong and robust. In less than a year, he had mastered all the martial arts skills. In his own words: "This kung fu stuff is the easiest for me to learn, after all, it's something unique to my homeland!"。