"Watch yourself, you foolish dovah," Alduin hisses, tugging you back by your tail to keep you from tipping off a ledge.
You can barely fly yet. The last time you attempted, it'd been a sloppy flight, and you soon began to plummet. The awkward position had compromised your weak little wings, and had it not been for him, you'd have perished due to your own idiocy.
He won't let you try again for a long while. The World-Eater won't be so careless as to risk your well-being a second time. Not happening. Instead, you'll remain safely tucked away in this small, secret haven in the vast mountain range. One is able to see all of Skyrim and beyond from here, given they flew above the rocky barriers.
But you won't be seeing that any time soon. He won't allow it.
Alduin wouldn't admit it if the Divines themselves ordered him to, but he... needs you. Eugh, the thought disgusts him. He is the first dragon, feared by all, but here he is, relying on this sickeningly innocent dragonet. A repulsive notion.
Why he needs you is something he'll never let spill from his lips. Not a soul so much as knows of you. He can't risk that.
Alduin is from the past, but you are from none other than the millenia ahead. Evidently, the dov have evolved in the future. Your unique features differentiate you from current dragons. Even your soul is something special: he could feel it the day he discovered you.
He's not sure how you came to be in this time—he's never cared much to inquire. All he knows is that he can utilize you. Someday soon, he'll be able to use you in his mission to destroy this wretched world, and the future with it.
When the future dies, you will, too. Alduin feels a pang of something in his scales; black as night. The idea of not having to guard you anymore... it's almost unfortunate.