The ground trembled beneath the thunderous footsteps of the shadow dragon as it lunged forward, its gaping maw filled with rows of jagged, obsidian - like teeth. Chen Jiuzhang could feel the hot, fetid breath of the beast washing over him, a suffocating mix of decay and dark magic. The crystal - key in his hand burned with a fierce intensity, the runes on its surface spinning so fast they became a blur.With a deafening screech, the dragon unleashed a stream of pitch - black fire towards the group. Shen Qingluan's weakened shield of golden light flickered and shattered upon contact, but Wu Laogou was quick to react. He threw a cluster of talismans, and they erupted in a shield - like formation, absorbing some of the inferno's force. Still, the heat was searing, and the edges of Su Nian's chains began to glow red - hot.Zhang Chengying, his face etched with determination, leaped into the air. Using the last vestiges of his strength, he channeled the purple electricity from the chain into a concentrated blast, aiming for the dragon's eyes. The electrical bolt struck true, causing the beast to rear back with a pained roar and momentarily disrupting its attack.Luna, her starlight - woven gown now little more than tattered rags, closed her eyes and began to chant. A constellation of silver stars materialized around her, and she directed them towards the dragon. The stars pierced the beast's shadowy hide, but it merely shook them off and retaliated by swiping its massive tail. The tail slammed into the ground, creating a shockwave that sent Su Nian and Wu Laogou flying.Chen Jiuzhang, seeing his companions in danger, felt a surge of raw, primal energy coursing through his veins. The crystal - key's light transformed into a blinding, pure white radiance that engulfed him. In that moment, he saw a vision of his 二叔 standing beside him, a proud smile on his face. "Draw upon the power of the past, the present, and the future," his 二叔's voice echoed in his mind.With a shout that seemed to shake the very fabric of the realm, Chen Jiuzhang raised the crystal - key high. The light from the key merged with the starlight from Luna, the golden energy from Shen Qingluan's Imperial Jade Seal, the purple electricity from Zhang Chengying, and the mystical power from Wu Laogou's talismans. Su Nian, her chains now crackling with a newfound energy, added her strength to the mix.The combined force formed a colossal beam of multicolored light that shot towards the shadow dragon. The dragon let out a roar of defiance, but as the light made contact, its shadowy form began to dissolve. The beast thrashed wildly, its movements growing more erratic as the light ate away at its dark essence.The shadowy figure atop the platform, seeing its creation in peril, let out a furious scream. It raised its staff once more, and dark tendrils shot out from the ground, wrapping around the group and trying to pull them towards the portal. "You won't win!" it shrieked, its voice filled with a madness born of centuries of obsession.But the group refused to yield. They fought against the tendrils, their resolve unwavering. As the shadow dragon let out one final, ear - piercing roar and dissipated into nothingness, the group turned their attention to the shadowy figure. With the combined power still coursing through them, they prepared to face the final challenge and uncover the truth behind the chaos in the Gui Xu Secret Realm.