A/N: Here it is - Final Chapter. Enjoy.

Just under five years had passed since Cas' 'Angel Mojo' had slowly depleted from his body.

Honestly he was surprised he'd survive this long but he had Dean so at least he wasn't completely alone.

Before the Croatoan Virus it had started with possessing Jimmy Novak's body, raising Dean from perdition and then meeting and befriending Sam and Dean Winchester. Bobby Singer slowly entered the picture and Cas accepted him in stride, Bobby had done the same. Cas hadn't spent much time with Jo and Ellen but did feel sorry for the Hunter family that they lost two good people that day.

How Cas still wished for some of those good days back, Sam and Dean's Brotherly bond was something even Angels could barely achieve yet Lucifer ripped them apart as if they were paper. Cas stuck by Dean's side and wouldn't leave unless told to, Cas is still waiting for that day to come but doubts it will.

Dean and Cas' profound bound was stronger now, despite Cas becoming the useless pathetic piece of crap he was. Dean fixed all the new-found developed faults and mended the cracks of Cas' mortality. No smooth sailings but it was more or less complete now.

Some nights they would stay in each other's company, no words were necessary among them unless it got awkward but silence was the option they leaned towards.

It wasn't due to the smoking of his drags, at least that's what Cas told himself at first but breathing became a hardship, he would cough or hack away through the darkness of the night. Sometimes it would last a few minutes, other times turn into an hour or possibly more and then slowly but surely it would last through the night.

His body acted as if he was having seizures, in his bed or on the floor or outside. Sleep was interrupted daily now, waking up sweating hard, wheezing or unable to breath Cas was always thankful when Dean was around, concern written all over his face while rubbing Cas' back trying to calm the distraught man down and help his breathing return to normal.

"De-an... he...lp me..." The ex-Angel wheezed out, his eyes wide and face was red.

"Calm down, first. In and out" Dean found himself repeating that multiple times but the words had an eventual affect on Cas.

Some night Cas was asleep curled up against Dean's chest to remember the concept of regular breathing but coughing fits pursued.

"D- De- Dean!" Cas begged in between hacking up his lungs.

The Winchester had to swallow panic and his own rushed breathing. Dean was secretly failing at his title of Fearless Leader when he feared for Cas' life and did sneak in to check on his best friend when things were quiet at Dusk.

During a Hunt for the Colt which was in the Resistance's grasp now after a Winchester 'interrogation' was hugely successful. The Winchester managed to slip away into a run down pharmacy and found two things that could potentially help Cas, inhalers - two sets were grabbed for emergencies and some adrenaline Epi-Pens for worst case scenario. Once or twice Dean had seen a hint of blue shading Cas' lips and was far too uncomfortable with the idea of always lucking out. The Hunt brought them one step closer to Lucifer as Dean had caught themselves an entourage member of Lucifer for some more 'interrogation' time.

Returning from the Hunt, his alone time with the Demon and finally being able to relax for a moment Dean found Cas sitting against his own cabin's far wall, shaking a little. Dean had to give Cas credit, he was able to handle being Human relatively well despite everything that was dumped on his plate.

"Cas, I got something for you" Dean strode over and crouched down next to the fallen Angel "Inhalers, they'll help when things get bad, now I don't want to have to use this but I also grabbed some Epi-Pens for adrenaline if it got out of hand.

"Understand?"

"...Yes, Dean..." Cas feigned confidence despite the shaky breath, Cas smiled and winked at Dean. The Winchester rolled his eyes and left Cas with the medication as he remembered he had to score off map locations and find out a little bit more information from his 'friend'.

"You... you know that... the D- Demon is sc- scared of you..." Cas nonchalantly brought up while petering out a cough.

"Good, then it isn't just Lucifer they should fear"

"You know... Alastair was wrong... all those years... ago"

"Don't matter, Cas. I've got to go. Try and not die before I get back"

"Alrighty"

One night, that was all it took.

Dean was prone to spending the night with Cas so A. Dean wasn't alone and B. Cas didn't swallow his tongue in his sleep or fail to breathe at night.

Cas was so still and unbelievably quiet, Dean wished he had noticed sooner as it had been enough time for the former Angel's skin to turn cool and lips had turned light purple.

Once again Cas was under Dean's brute force of CPR, the Epi-Pen was out of it's case and ready to be used, the inhaler was resting on Cas' stomach while Dean pumped Cas' chest, after the thirty compressions and two breathes, the inhaler pump was pressed once then again after a space of five seconds and then pressed again. Once complete Dean would elevated Cas' head for ten counted seconds. Lather, rinse repeat.

It took far too long for Cas' bluer than blue eyes to open once again, his skin to return to their normal pigmentation and for his lips to fade back to pink whilst grasping at whatever oxygen he could. Dean eased the shaking man up to his chest to sit up. Both ignored the tears, Cas gripped Dean's left shoulder as tight as physically possible in his weakened state.

"I got ya," Dean murmured into Cas' dirty and matted hair.

"Dean..."

"Shut up, Cas. Save whatever energy you've got left, we'll need it for when we take on Lucifer. I'm sure I know what you're about to say but just focus on breathing right now"

Cas regained control of his breath and curled an arm absently around Dean, all of his words long gone after Dean had ordered him to shut up.

Cas knew taking Lucifer down would be the end of him and possibly all of the Resistance. They trusted Dean, their Fearless Leader and would follow him on the battle field it was just a waiting game now and their time was almost up.

Extra Note: That's it - Story complete.

I was going to keep this story afloat for as long as I could and I think 15 Chapters is good enough as I didn't want repetitive Chapter Ideas going around.

I will be starting the AU 5X04 soon... If wanted if course.