Hades had just been watching the entire time. And had been just been observing them. He learned that there was a distinctive difference in these humans physiques, and realized it was a gender difference, and could only now identify the ones who captured him to be females.
He had only killed those two fools before because they stepped in his food, which was undoubtedly a provocation to him. He let the others go because he did not need so many people dead, and 2 corpses would be enough to feed him, as was the thoughts of his abyssal mindset. When they turned their enmity to Chen Yan out of subconscious fear, he decided he had nothing more to do with them if they did not provoke him.
He did not consider helping Chen Yan, as he thought that he only needed to keep one human safe as per the contract, and that one human was more than enough to get information of this world, and he had no feelings of attachment to Chen Yan. Chen Yan too, did not consider asking for his help, as she had only known him for a few eventful hours, and subconsciously did not consider him an asset she could use and trust.
Then that foolish girl decided to protect her sister, despite how weak she was and that she could have been let go. He could feel a bravery in his heart that he knew originated from Ling'er, and was felt by him through their link.
He could not understand why they would protect each other so vehemently. In his world, most siblings were enemies from the moment they were born, as they competed for the meager resources their parents could give. He himself had personally felled his siblings.
He had long since realized this world was too different, he had no choice but to learn more.
Ling'er called to him, she was in danger now, so he had no alternative but to act.
The moment the pack of humans turned their heads, he was already in the air. In the dim lighting of the room, he decisively clung on ones chest with his claws, and tore into his throat with his small, yet terrifyingly lethal fangs.
A scream of agony rang out as blood sprouted like a fountain, and the others of it's pack shouted words he didn't understand. Hades decisively decided to learn their language later. The human pack's eyes turned red as they unhesitatingly raised their claw like weapons. Their inhibitions had evidently died with the death of their pack mate before their eyes.
He fell to the ground nimbly and darted backwards. He would not carelessly challenge all these humans at once, he knew how mystical they could be.
All their attention was on him now, and the girls were no longer in danger, and just watched for some reason Hades couldn't fathom.
The humans had splendid coordination and worked together with evident experience, and their strength was more than enough to sever his waist in one blow, but were clearly not used to fighting inhuman opponents, they clumsily stabbed at the ground and tried to kick him, but the movements were too simple to Hades.
He had already observed their techniques before when they battled Chen Yan, and already understood the range of the weapons, and their feet were too monotonous to graze him.
He quickly found an opening in the barrage of blade light and slipped near their feet, making it far more difficult to aim at him without harming their comrades.
That hesitation was all he needed to climb up the human's body with familiar swiftness and tear into his throat, ending his life just like the other.
But this time the human dropped his weapon and decisively grabbed his body while his fangs were still in his throat.
His comrades shed tears as they they took the opportunity to chop down at him. Hades was not inexperienced with fighting multiple enemies at once though.
He leaned backwards, allowing his weight to pull the dying human in to lean forward, thus changing his position and putting the corpse in front of the blades.
The humans trembled as several weapons pierced their comrades body, and blood flew everywhere from the body as he still smiled and looked warmly at his pack mates without blame.
He said something before his eyes closed, and the humans seemed to make more battlecries and shed waterfalls of tears as they raised their blades once more. How foolish. They seem hopelessly attached to one another, and even after losing almost half their number, leaving only 3, rather than retreat from a hopeless battle they chose to fight to the death. Were humans more stupid than they let on?
He fell to the ground, on his feet once more and dashed toward his next victim. The one in the lead, the one with yellow hair, was his next target, he seemed to discuss something with his two remaining allies with gritted teeth.
"Haaaaaaah..."
He held his blade before his body, facing Hades with admirable determination, and began to let out a low roar that grew louder with every second. A blue aura rippled from his body as his muscles pulsed strangely and his eyes glowed a deep blue.
He did not intend to let him finish this bizarre transformation, and leaped to kill him. But the other two intercepted him, swinging their blades at him at the same time.
Hades immediately spread his wings and used the splitting air from the blades to carry his body in a horizontal spin, at the same time lashing his tail in a circle, using the tail blade he hid from them all this while.
Without any suspense, the blade that mysteriously extended slashed through both their throats. But instead of covering their wound to stem the blood loss, they continued to split the air with unwavering ferocity. With paths like a pursuing shark, they headed toward his body while he still spun in the air.
He did not panic though and and fueled his wings, lowering his surface area. His tail that had just slit their throats had already gone full circle, and now wrapped around one of the humans arms. He pulled the arm, leaning the blade in its hand to a direction of his choosing, allowing it to pierce just past his head, and at the same time, intercepting the other mans blade, which instead sunk into the his comrades arm.
They had no more energy left, using it in their last attack, and said some words in their human language before blood spurted out their throats and they collapsed to the ground in a pool of their own blood.
"HAAAAAAAAH!!!!!"
But they seemed to have served their purpose. In this period of time, the leader of the pack, the last man standing, had completed his transformation.