Much later it becomes clear why Thor does not recall anything of his mother's second pregnancy or his brother's birth, though he does have a vague early memory of being with her while his father was away at war. But he treasures his first coherent memory of Loki, especially when darker days come and joy seems elusive.
Loki is still a baby, with wispy black hair, round cheeks, and big pale eyes that hold only innocent curiosity. He stands on unsteady little bare legs, clutching the settee with two chubby fists. He's been pulling himself up on the furniture for weeks, scooting along the edges of everything he can reach, not much slower than his lightning-fast crawl.
Thor wonders if Loki walking is what his mother truly wants, since no one can keep up with him already. He has managed to find ink, giggling as he dumped it all over the rug, and soap which made him cry when he ate it. More dangerously, he's pulled over two stands, once nearly smacking himself in the head with the heavy ceramic basin, and he was found next to a bathing pool, chewing on the handle of a scraper and sitting a handspan away from the water on the rim, despite the gate meant to prevent exactly that from happening.
But his mother seems to think Loki's ready to walk and merely needs some encouragement. So Thor watches from the couch, as Frigga kneels a little distance away and holds out her arms to Loki, smiling. "Come, sweetling, can you walk to mama?"
Loki lets go, prompting her wide smile. But manifesting a stubborn contrary streak, he heads straight for Thor instead. Thor slips off to kneel on the floor, delight catching in his chest like molten sunbeams, that Loki is coming to him, even though he's farther away than their mother. He holds out his hands, grinning, and curls his fingers in excited little gestures to coax him as if he's some kind of hound, "Yes, yes, Loki, to me."
Frigga exclaims with proud excitement, "Look! He's walking!"
It's an ungainly, bowlegged walk, more of a tiptoe stagger than a proper walk, and once he's going, he doesn't seem to know how to stop. Thor laughs. "Yes! I'm here, I'm here, come!"
He reaches Thor's hand and that breaks his momentum, so he falls to his padded rump to the tile. For a moment he's startled by the abrupt end of his adventure, looks like he's considering being upset about it, but before he can cry, Thor snatches him under his arms and pulls him to a chest bursting with pride. "You did it! Loki, you did it!"
Loki laughs as if walking is the most joyful thing in the world, and Thor tightens his embrace. And though Thor is not that big himself yet, Loki feels so tiny and fragile against him, Thor is nearly overwhelmed by his need to protect his baby brother. "Always," he whispers into the soft raven hair. "Always you can come to me, and I will keep you safe."
Frigga embraces them both. "I am so proud of both of you." Her voice breaks a bit as if she might cry and she kisses Thor's cheek,
Thor closes his eyes and wants to remember this moment forever.