Here's my take on what happened last night (quotes in italic, my comment in underlined):
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As the God Apollo (Kantor) looked down from his pantheon in Mt.Olympus, he saw a dark figure hiding beneath the caves, speaking with another individual who was familiar to the God. With his bow steady in his hands, he moved his way down the summit of the mountain. He could hear the two shady figures' voices getting higher and higher. It seems that they were in a heated argument.
"Who goes there ?!" claimed Apollo. The two shady figures stopped talking, and turned to the overconfident God. Before he could speak another word, one figure lunged at Apollo, stabbing him with a knife. "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.
As the dead God's body exploded, the cave it was in crumbled, shaking the very foundations of Olympus.
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This is the weirdest of all the deaths, the fact there was two persons involved in the killing makes this complicated. Roles that could fit with this could be Siblings with one being evil and the other being good but that would be a pretty sucky role for the good brother since if he tells on his evil brother, he's killing himself too.
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Alerted by this unpleasant occurence, Poseidon (patapon) and Zeus overlooked at what was going on from the highest balcony on Olympus. Poseidon caught a glimpse of a small figure rapidly moving up the sheer walls of the Mountain.
"For the Glory of Olympus !" Poseidon jumped down into the sea below and summoned his Leviathans, attacking the person who was ascending Mt.Olympus. However, the Leviathans were no match for this skilled warrior, who picked them out one by one. At a time Poseidon was charging up his deadly burst of electricity, the man took a leap of faith straight at Poseidon, and started stabbing his chest repeatedly. Poseidon who was imbalanced by this unexpected maneuver fell near the entrance of Ares' tomb where the man slowly approached him.
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I'm guessing we can scrap the idea that Kratos is simply scared of comming out to be cured because he decided to be evil and killed last night (or maybe he's forced too kill).
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Meanwhile Zeus flew down as the warrior and Poseidon were battling only to find the Kronos (Khuutra) climbing the mountain in its opposite side. "I banish you to the darkest depths of Tartarus !" Zeus let out a screeching thunderbolt at the titan, however, much to the his surprise, it was ineffective. "Hahhaaaaaa ! Is that the best you can do my son ?" Kronos asked. "YOU will be the one dying today !" As Kronos snatched Zeus out of the air, and started crushing him, A sister of fate became aware of whats going on. The death of Zeus simply couldn't be allowed.
She stormed towards Zeus' thread of fate and was able to change its orientation slightly. As time moved back, Zeus's thunderbolt burned Kronos' arms and the titan fell down the mountain and into the depth of Hades.
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Since I'm thinking Zeus is not a player. What I think happened is the player with the role of Sister of Fate targetted and killed Khuutra. GodofWar just put Zeus in there to fit the story.
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Hermes (Final-Fan) who hadn't completed his task set by Zeus knew he was in trouble, as he exited the bedchamber, and started casually walking around the high grounds of the city of Olympia like he always does, he saw something quite odd, happening near one of the caves of Olympus as he walked near the ledge to see what was going on, he was grabbed by someone clinging on to the edge of the ledge, and pulled down, as the Messenger of the Gods fell down screaming and was about to hit the floor, he was caught by the very person who pulled him down. Before he could react, the God had his limbs torn off as if he was a rag doll and succumbed to his rather gruesome injuries.
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Looking at the description here, especially the "limbs torn off as if he was a rag doll" part, what I make of it is that Final-Fan was killed by a Titan, probably Khuutra while he was falling down to the depths of Hades.