Ok, I know now that orange is definitely the color of the SK aka Kratos. Why? Simple.
He was the one who killed Poseidon.
Based on the other kill, we already know that Kronos (Khuutra) was killed by the sisters of Fate. How they did it is the only question. I assume by reversing his attack, Kronos tried to attack Zeus but the Sisters of Fate sent the attack back to him. That would mean they can sent every night action back to the user. Other is Sisters of Fate.
Murdered reads like an ordinary kill. Nothing of the text where Hermes (Final-Fan) sounds like there was a special condition involved. I'd say that was the ordinary mafia kill.
Now between Massacred and butchered it's getting harder to decide. But after reading 3ever's story it becomes clear.
In the story, Apollo (Kantor) looked down to two shady figures talking. TWO shady figures? As far as I know, the Serial Killer always acts alone. This becomes even more clear when we take Kratos as example. Additonally, read this part:
"NOOOOO!!!!" The other yelled and desperately tried to pull the assaulter away from the wounded God. However, he had been mortally wounded by repeated stab wounds and the shady figure fled from the scene, laughing as he did.
The remaining figure, who was not fond of his comrade's ways, stepped forward to end his suffering. He could easily call someone to heal him, but that would only lead to more questions and trouble. The shady figure slit Apollo's throat, and disappeared into the depths of the secret cave."
This implies several things again. Firstly, the second shady figure was clearly against the kill. He tries to pull the assaulter away. This would mean that the killer of him worked together with a Vigilante or another pro-town role. The second part supports my theory: "He could easily call someone to heal him, but that would only lead to more questions and trouble." Sounds like the second shady figure was indeed pro-town and didn't want his death, but nobody would believe him when he tries to explain it. That's why he decides to flee from the scene.
That would mean "butchered" means either Vigilante kills, or another fraction that is able to kill.
And that leaves "massacred" as the only remaining killing style.
As somebody else already pointed out, Poseidon's (patapon) killer was a "skilled Warrior" who defeated the Leviathans one by one and after that, stabbing Poseidon. at the end of the story, it becomes even apparent:
"You will never succeed. For everyone you kill, there will always be another to oppose you !" Poseidon yelled out. The man smirked, and approached the weakened God of the Sea and started beating him up with his bare hands. Poseidon attempted to electrocute his attacker, failing miserably. As he started crawling away to the sea, his only hope of survival, the man grabbed him by his legs, pulled him close and gouged his very eyes out. "
If you ask me, that sounds just like Kratos way of killing.
And with this, ladies and gentlemen, we alread know that:
Murdered means Mafia kills
Massacred means SK kills
butchered means most likely Vigilante kills
other means Sisters of Fate.