It had been Sam’s idea: Cas would tackle the issue with Abaddon whilst he went and stabbed an angel blade through Metatron’s face from the pair of them. Cas had argued initially; he had a score to settle with Metatron, but eventually he’d conceded. Heaven against Hell; Humanity against Heaven.
It made sense, they’d agreed. Cas was an angel again these days and though once upon a time he might have played fast and loose with the lives of the Winchesters, there was now far too much at risk. They wouldn’t leave Sam’s fate in Dean’s largely unreliable hands. Which is to say Sam wouldn’t leave his fate in Dean’s hands any longer. That ship had sailed the night Gadreel had burnt the life out of Kevin Tran’s eyes and Sam had had to sit idly by and watch his own body kill a kid he had called brother.
Sure, Kevin had absolved him of any fault but if Cas knew Sam, and he liked to think these days he had a pretty good grasp on the youngest Winchester, then he knew - forgiveness from Kevin or not - the Prophet’s death still weighed heavily on Sam’s mind. He also knew it was likely Sam would carry that guilt for years, just another cross to bare on shoulders that still hefted the remnants of demon blood, Lucifer and the apocalypse.
No, the duty of ending Abaddon would fall to Cas and Cas alone. It was labelled under the guise that Cas would be able to take out Abaddon far more easily than Sam would. After all, angel’s are cold and they’re detached, regardless of a short stint at humanity.
And Cas… well it’s not like he hadn’t had the practice.
A thousand times over in fact.
Sam had headed out in the Impala with Crowley - Crowley of all people. They’d traded off Cain’s blade to Cas, and they were heading five hours south east to Parsons, Kansas, where Malachi had amassed his angel army and were planning on taking down Metatron’s own. It was going to be brutal, but if it all went well, they had the necessary ingredients to reverse the Scribe’s spell and restore the angels to heaven.
It helped that they had a hidden ace up their sleeves. Gadreel was an untrustworthy ally, but he had whole heartedly shrugged out of Metatron’s clutches. Not that the aforementioned angel had any idea, though there was still time for the half cocked plan to go terribly wrong.
But Cas knew it would succeed. He had faith in Sam. The thought brought him a strange sense of comfort. He may no longer have faith in his Father or the angels, but he’d found faith in a brother. Even one that had been born for Lucifer.
Cas had laid the trap for Abaddon in an abandoned barn close to the bunker and waited. And the Knight of Hell didn’t disappoint.
Abaddon paces against the edge of the elaborate Devil’s Trap, that’s reinforced by Enochian scrawled in angel blood. Dirty, but it’ll do the trick. There are sigils staining every available surface, trapping the Knight completely.
Briefly, Cas can’t help but notice the similarities. The symbols sprayed over every surface, the rattling wind against the steel roof… all it needs is for the lights to blow, for the demon blade to be rammed through his chest and it’d be just like old times…
“Hello Dean,” Cas says.