"You got a death wish, pal? Nobody intrudes my lair for no reason and lives to tell about it!"
Syndrome is furious about the intrusion of the Hero Killer Stain in his lair. In fact, he dropped in unexpectedly and slaughtered his minions just to get to him. The thing is, even if he is furious with him, he is afraid of him deep inside. This is because even if they're both hero killers, Stain won't hesitate to murder criminals as well.
"Oh, I do have a reason, Syndrome," Stain muttered.
"And what's that?!" the redhead started shooting a zero gravity beam from his fingertip, but Stain is fast enough to dodge it by sidestepping.
Next, the latter threw a small knife at his face.
"Ow, my face! My handsome face!" Syndrome growled. "You're gonna pay for that!"
As he shot another beam at the Hero Killer, Stain dodged it again and attempts to slash him with his katana. Syndrome flew up to the air to dodge the attack, and he attempts to lunge at him. However, that doesn't stop Stain from getting a hold of his small knife and licked the blood that was lingering on it, causing his opponent to be paralyzed.
"Hey, what gives?! I can't move!" the redhead realized as he started losing control of his flight due to the paralysis on his body. As a result, he crashed into a wall.
"This is my Quirk, Bloodcurdle," the brunette responded calmly. "All I have to do is taste your blood, and that will leave you paralyzed in an amount of time depending on your blood type."
"Why are you doing this, Stain?" Syndrome demanded. "Aren't we both hero killers?!"
"Sure, I kill heroes, but only those who I considered 'fakes'," was the response. "In fact, I'm planning to make a society of 'true' heroes by killing the 'fake' heroes. I heard what you're planning, Syndrome. Sure, you killed these heroes, but all this because your favorite superhero rejected your offer of being a sidekick? That's petty."
"But what about you? You did all this because you felt heroes weren't becoming heroes for the right reasons."
"Yeah, but for a villain like you trying to be a hero as you kill all those heroes, that makes you a criminal, and I won't let you use your power idly like that."
With no hesitation, Stain pulls out his katana and raises it above Syndrome's head.
"Goodbye, kid. May your death sent a message in the world to give back their heroes," he said.
"NOOOOOOOO!" Syndrome shouted his last word as the Hero Killer stabs his back, finishing him off once and for all.
Satisfied, Stain leaves the island through a stolen aircraft.