Prompt: "Illya becomes the master of Asterios. Either really cute, really angsty, or whatever suits the writer's mood. I want more big fluff content in my life." — Natsu, answered by Yuki (YukiKazami)
"Ah... Master..."
Berserker gently prodded her face as she rested in his arms, tired after a long day of "patrolling" with her "older" brother. Illya instinctively turned away, murmuring as she attempted to grasp at the last dregs of her dreams. Faded bits still filled her mind, endless dark halls contrasted with a familiar white forest. A particularly vivid moment came to her once again, a flash of bronze skin and white hair dashing back and forth across the snow. Even then, she had noticed his true nature. Only the wolves that had touched her were harmed.
"Come now... Wake..." A small smile came across the face of the gentle giant as his charge pouted at his insistence. "Wait until... home..."
"Fine, fine, I'm awake. You do make quite the fine bed, though." With a yawn, she stretched her tired limbs before moving up to her usual position on her Servant's shoulder. "What do you think of Onii-chan, Berserker?"
"Kind... Good food..." Asterios's grin widened as he remembered the feast that Shirou had prepared for him out of gratitude for keeping his sister safe. "Not who... you thought?" Despite his rather paltry conversational skills, Asterios was not an idiot, and he could certainly tell that his Master's initial mindset about the war had changed dramatically.
"...no, I suppose not. Just one more thing to hold those rotten golems accountable for when I return to Germany to end the Einzbern line." The revelation that her father had been desperately trying over and over again to save her had sobered Illya's bloodlust once she worked past her initial disbelief, and her brother's warmth had done wonders to heal that long-standing wound. "...thank you, Berserker, for standing up to me, that night near the church. If I had attacked him then, once that Tohsaka girl left, I would never have known the truth. Everyone writes about the minotaur's wrath, but I suppose you've got more of a soft side than legend wants to admit."
"You're… welcome… Illya." A gentle shade of red tinted his cheeks, but his smile grew even larger. "Must protect… you. Your heart… too."