+ Doctor Who / Thor Crossover (WHAT IF: FANDOM AU) || Part I, II, III

What if: The Doctor had visited Loki numerous times during his long life span, bringing him along to adventures and sharing the universe with him. Unfortunately, one day when Loki needs him, the Doctor doesn’t come to help. (Around the time he realizes that his father had been lying about his real heritage.)

“You’re too late, Doctor." 

+ Doctor Who / The Avengers Crossover (WHAT IF: FANDOM AU) || Part I, II, III
Music that fits the scene [x] (We Must Be Killers by Mikky Ekko)

What if: The Doctor had visited Loki numerous times during his long life span, bringing him along to adventures and sharing the universe with him. Unfortunately, one day when Loki needs him, the Doctor doesn’t come to help. (Around the time he realizes that his father had been lying about his real heritage.) 
Devastated that even the one he trusted the most did not come to his immediate aid, Loki does what he thinks is for the best - to try and gain his father’s approval. But this causes destruction and chaos to form a tight bond, wielded concisely by Loki’s thirst to succeed.
When the Doctor finally arrives, he is all but too late.

(Cont.) The Doctor and his trusted companions, Rory and Amy, arrive in the modern time US where a certain God of Mischief had broken out of his confines. They team up with S.H.I.E.L.D and later with the Avengers Initiative, as the Doctor is considered one of the many talented beings to protect the Earth from all harm.
The team manage to capture Loki… but all too easily. The Doctor knows something is wrong and tries to warn the Avengers, who have the same thought in mind. However the power of the tesseract causes confusion and anger to pass through each team mate. While they argue, Amy slips away to face this God of Mischief who had the power to bring about such chaos, even in the Doctor. (Rory doesn’t notice Amy is gone because he is just as caught up in the furious argument.)

“Why are you here?” Amy demands as coldly as she can, trying to hide her uncertainty. Loki, who had taken a seat inside his glass cage with the calm of one who had the upper hand, watched her with a slight narrow of his eyes.

“Amy Pond. The Doctor’s newest companion. It is a pleasure to meet you at last.” Loki drawled with a slow smile. It made Amy’s skin crawl.

“You haven’t answered my question. You came of your own accord, that’s pretty clear when the Doctor became suspicious of you. So you can tell me what your true intentions are right now and less harm might come to you if you do.”

“Harm? Such irrelevant objects of so-called destruction your kind wield is of no use to me. Only magic can truly be my enemy, and I wield such elements with ease.”

Loki stood up now with an swift elegance that no mere human could have mimicked. Amy never took her eyes off of the God, even though she knew she was - or at least she thought she was - safe. Maybe it’s time to try a different tactic to approach him, she thought. 

“The Doctor told me that you’ve been misguided.”

A dark chuckle escaped Loki. “Oh, did he now?”

“He said it was never your fault that you were born the way you are.” Amy said slowly, watching Loki carefully. The God was definitely not smiling now.

“I see the Doctor has once again tried to take away my misery with false accusations.” The God of Mischief “I do not need his help.”

“It’s what the Doctor does. Fixes things.” Amy says it without actually thinking it through. Because it really was true.

“If that is true, he would have done something to fix your infertility.” Loki’s eyes glimmered knowingly.

Amy stood her ground as much as she can. Of course she shouldn’t surprised that a God knew about her… inability to produce offspring. Yet it still caught her off guard.

“Why do you think that is so? If he is so good at fixing things, then surely a solution would have already been discovered. Yet here you are… He is not what you think….” Loki hissed and the next words that came out of his mouth were dripping with poison. “The Doctor always lies.”

Before Amy could even speak, Loki continued, an ugly snarl of a smile spreading through his face.

“You must be aware that the Doctor will eventually dispose of you and your insignificant husband? You are mortal… and he is a Time Lord. Your small lifespan will eventually burn out but he will leave your side before that happens.” Loki spoke these words as if each syllable tasted of the richest wine imaginable.

A tear fell before Amy could stop it. She glared at the God, anger boiling quickly to the surface. She knew that in between the lies, Loki was right. She was mortal and the Doctor… well, he was an alien who never aged and travelled with the world. She always feared that some day she will never hear the call of the Tardis.

But Amy knew better than to fall for such a trick. Because this was, after all, a game being played by the God of Mischief. She had been with the Doctor long enough to know that he is never heartless and without purpose.

Perhaps her resolve had shown on her face or perhaps it had not but Amy saw a slight frown crinkle the edges of Loki’s lips.

“I see the Doctor has chosen well. Enough to abandon me during my imminent triumph to rule over Asgard as if I were a worthless object. For I am an artifact, left behind by a ancient war long since past..”

Amy almost felt sorry for him if not for the growing smirk that now tarnished the momentary vulnerable look on Loki’s face.

“I will kill everyone you love and hold close to your heart. And when I am finished with them, I will burn you to ashes in my hands.” Loki’s green eyes glowed deep blue, shimmering dangerously within his pupils.

“Then you’ll be feeling my wrath. No one touches my wife.” A familiar voice came from behind Amy and she saw Rory standing there, a look of determination clear on his face.

“Such weightless words and false hopes. What have I to fear?” Loki says mockingly.

Rory moved forward, close enough that Loki was inches away from the glass. “Us. And we’re not alone.”