Wrath of Eighteen - Rant Book 4.0

I expected it to get dark but not THAT Dark

Rassilon couldn't think, couldn't move.
Couldn't speak.
Couldn't do anything.
Grief flooded his body as he collapsed, sobbing over the body of his dead friend. "No. Alfons. You weren't supposed to die like this."
He buried his muzzle in Alfons' still warm fur. "Not like this. At the paws of..." He trailed off, choking on his breath.
He had to collect himself. Stay strong. Stand up.
He faced Whisperstar in fury. "It was you wasn't it?"
The black and white tom didn't even seem to want to defend himself. Rassilon unsheathed the claws on his left forepaw, reaching up to his face to reopen the freshly healed cut on his face. Warm blood dripped down his face moments later. He wiped it off, watching it as if it were some sort of unusual prey.
Then he looked up again- Whisperstar looked frightened now- and tilted his head. "Oh, you're frightened now, aren't you?"
He stepped away from his friend, unsheathing the blade that had been previously hidden before, walking slowly closer to the WindClan leader, who backed away to the Highrock.
You gonna defend yourself now?
"You should stop. This-this is a mistake." Whisperstar's fur puffed up in defence. He knew he'd could move, but chose not to, or couldn't.
"If it was a mistake, as you call it, " Rassilon glanced at his friend's body near the middle of the clearing. "He'd still be alive."
Whisperstar opened his mouth, but was abruptly silenced. Rassilon had plunged the blade into the leader's chest, not stopping until he'd reached the rock behind, pinning Whisperstar.
I'm sorry, Whisperstar. Equivalent Exchange. Your life for his.
He slid the blade away, out of Whisperstar's body, watching coldly as the leader's now bloodied body slumped to the ground.
"Brother! You should've-"
Rassilon turned to face a red cloaked golden brown figure. Long Branch. His brother.
Rassilon looked at the blood on his paw, then to his brother.
I'm sorry, Long Branch.
I lied.

Maybe alchemists are murderers.

Here Lilian-Nightshade this is the story I was talking about