A child needs companions
When Thor was ten, the botanist Ewen Strongarm from Vanaheim came into the city, bringing with him seeds of rare Vanir grasses that would blossom and bolt in the spring, making more seeds that could be ground into bread, delaying the onset of starvation for the People. He brought his son, Hogun Strongarm; and he brought a Vanir fever with him that most children snuffled through for a day or so, then got well. Thor and his comrades promptly adopted Hogun into their troop of child-adventurers. Loki agreed to help Hogun with his schoolwork, so that he could learn with his friends. And Loki caught the Vanir fever, and did not get better.
Finally Frigga called Eir, the healer, to the palace. Eir looked, and listened, and collected effluents; then gave her pronouncement. “Someone must have not cleaned their muddy boots. It is a mild Vanir ague, and most Asgardian children get it but once.”
Frigga looked at Odin, then back to Eir. “What of other races? Say, people who are part Jotun?”
“Oh, it takes the Jotunns very hard. I remember reading your mother’s notes, Odin.”
Odin said, “I believe I caught this ague on my first trip to Vanaheim. I had it harder than most, and the healers there prepared a draught for me that helped immensely. Mother said that my Jotunn companions must have rubbed off on me.”
“You must know that Loki came from Jotunheim,” Frigga said. “He is certainly part Jotunn.”
“Let me see if I can re-create your draught, then, King. In the meantime, he can certainly see his companions, if he has the energy. They will not get him sicker.”
It still took some weeks for Loki to heal. Thor brought assignments and read to him; Hogun brought problems to solve (and apologies for getting him sick); Loki read to Hogun. Fandral, Volstagg and Sif came a few times in a clump, to play with his toys and tell him the school gossip. Loki grew pale, and, on recovery, never again tanned in the sun. (At least he still enjoyed its warmth on his cool skin.)
When Thor was twelve, his schooling extended into the afternoon, when he was required to attend royal council sessions. Thor’s other companions—Volstagg, Fandral, Sif, Hogun—were not permitted to attend, although Loki could not be held away from these meetings. Loki insisted on participating—loudly—if he disagreed with the direction any deliberations were taking, so various of Frigga’s handmaidens took to attending as well. Gna was the best at transmitting Loki’s concerns to his mother; Fulla was the best at shutting him up. “Listen twice, talk once,” she told the smaller prince. “Someone else may bring up your concern, so that you don’t have to.”
Loki was returning from a taxation meeting, about a month after the brothers started attending them, when Sjofn asked him to visit his mother instead of fetching his hunting gear with Thor, who had an expedition planned with his friends.
“Just me?”
“You can catch up with your brother later, Prince.”
That was satisfactory. Loki walked ahead of her into the room, and found his father there as well.
“Loki?” Odin asked. “Do you know why you are here?”
“No, sir.”
“I’ve received reports from the various councils, as well as your mother’s associates. I’m concerned about your education.”
“Have I been too loud? I’m sorry, Father, it’s just…sometimes they are stupid.”
“Loki.” Odin knelt before the boy, lifted his chin so they could see each other eye-to-eye. “I know it is boring. I never meant for you to be frustrated, this young. Are you satisfied with the library?”
“Yes, sir.” That was another thing. Thor could tire himself out, with training and practice and play; but Loki’s mind didn’t stop at night. (Also, Thor snored.) A sheepskin-covered chair in the library, near the fire and with plentiful candles, was his usual roost after dinner until Odin or Frigga called a servant to take the sleepy boy to his bed.
“Well. You know that the people have great hopes of you. So do I. So does Frigga. When you can keep a secret, the next stage of your education can begin.”
“The next stage? You mean there’s more?”
“A whole field of endeavor awaits you. Magic.”
“Magic?” Even the word was a siren song. “What about Thor? Can he learn with me?”
“No, Loki.” Frigga sighed. “Thor has a good mind, a good heart, and great enthusiasm, but he hasn’t a magical bone in his body. He is blind and deaf to such things.”
“Why?”
“Everyone is different. Thor has no magic, but you will have enough for both of you. More than enough.”
“When can I start, then? How?”
Odin chuckled. “Let’s start with a little test.” He held out his hand. “How many fingers do I have?”
“Um, five? No, four. No. Six??”
A wave, and the hand was back to five fingers. “Good, you can see my illusions. Now, I am going to turn Thor’s nose purple for a week. Only you will be able to see it. If you can go the whole week without telling Thor or anyone else, or indicating in any way, even by laughing or smiling, that something is amiss with his appearance, then you will be ready to learn more.”