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The mission seemed simple: recover a rare ingredient held by an ancient Nordic deity for one of the Winchesters' spells. Of course, the mission turned a bit sour when the magical being, hiding in the form of a fifty-year-old man in a village in northern Washington State, realized that someone was trying to steal his precious resource.
He had tried to kidnap Jack, surely unaware of the extent of his abilities, and the operation turned into a bit of a bloodbath after a hand-to-hand fight, due to complex spells that prevented the angels from using their powers around and inside the house.
The deity ended up agonizing on the floor, pierced by a blade, after having still managed to sever Jack's entire forearm with one of his particularly sharp and ancient swords.
Castiel didn't have to search long to find what he was looking for, then showed the object into his coat after showing it to Jack.
"Can we go buy some food before we leave? I'm hungry." Jack asked, heading for the exit.
"Of course. I saw a store a few blocks away."
Already walking down the street, Castiel caught up with Jack.
"Jack, you should regrow your arm."
Jack barely slowed down, glancing at Castiel. He noticed that Castiel had healed his own injuries, which were much more superficial than his own, probably as soon as he left the perimeter established by the deity.
"But I thought we could let our injuries stay and give them an excuse to fuss?" He replied honestly, remembering what Castiel had told him during one of their previous missions.
"Minor injuries are fine. Major ones like limb loss will cause undue stress."
"Ah. Got it." Jack looked at his bloody arm and torn coat, then concentrated on rebuilding the flesh. The bones reformed, the skin then covering the raw skin.
Castiel nodded and they continued walking in silence for a few seconds. Then, Jack, looking concerned, turned to the other.
"But... at what level of injury should I start healing myself?"
"A missing limb, an open wound, also if there is a lot of blood. If you don't have time, you can usually see it on their faces when it's too much."
"Hmm..."
"You see, for millions of years, before modern medicine, a major injury would often lead to death, so they are programmed to worry about it. But in the case of smaller injuries, taking care of them can be a vector of social bonding."
"I understand, it makes more sense now."
"The supermarket is here. Let's go."
About ten minutes later, Jack had bought and eaten a moderately appetizing pastry. The two arrived in front of the bunker, next to where the Impala was parked.
Sam, who was sitting at his computer at the living room table, paused in his typing to welcome them.
"How did the mission go?"
Castiel placed the ingredient on the table. "We got it."
"What happened, Jack, what is that?" Sam asked, frowning, his gaze fixed on the coat, still torn at the wound and stained with blood.
"Oh, this? It's nothing, I hurt myself during the fight, but I regrowed my arm. I'm fine."
Castiel sighed as Sam's eyes widened.
"What?! You lost your arm?"
"Yes, but I healed it myself, I'm fine!" He was quite proud of himself actually.
Apparently, Sam didn't seem pleased to hear this, and Jack was now confused by his reaction.
Castiel moved closer to him and whispered, "Jack... I forgot to tell you, but telling people about this kind of things also causes excessive worrying..."
"Oh." He turned back to Sam. "Sorry. Forget I said anything, I'm going to my room." And he slipped away, leaving the two adults alone.
"Cas, you'll have to explain this to me."
Castiel sighed again. What trouble had he gotten himself into now? Parenting a nephilim was definitely not for the faint of heart...