It's not that Thor had no awareness of – or interest in – seidr. Not when his younger brother was one of the most cunning sorcerers in the Nine Realms; from the moment Loki learned to play with shadows and illusions, honing his sly wit and guile on his hapless elder brother, Thor had been forced through sheer self-defence to recognise, if not see through, at least some of his brother's tricks.

Rather, Thor had no head for it; he always had trouble grasping the fundamental laws and concepts, most of which required thinking about the world in ways that made him feel uneasy. Theories that Loki grasped with intuitive ease left Thor baffled and frustrated, and abstract hypotheses made him long for the solid reality of his hammer.

(Really, brother, Loki had said once. Do you honestly believe Mjolnir nothing more than a hammer?)

Their tutor in the arts had declared Thor hopelessly inept when they were still no more than boys. However, Thor had determined that before he gave up on matching Loki's skill, he would set himself to master at least one spell.

When Thor set his entire heart and mind and will on an objective, very few things could ever resist his determination. Seidr was one of them. Loki, sly, elusive, opaque and unknowable, was the other.

Thor eventually learned – with Loki's amused assistance, and after many, many months of endless practice – to call fire, the first and most basic spell ever taught to seidr-wielders.

He never learned to understand Loki.