The Frozen movies may have explained that heroine Elsa’s magic comes from her mother’s side of the family in the sequel, but it's left to a prequel to the Disney movie to reveal why Frozen 2’s villain hated magic. Released in 2013, Frozen became an instant hit for Disney and made an overnight icon of Queen Elsa, the movie’s more sympathetic twist on the Snow Queen played by Broadway legend Idina Menzel.
In 2019, the long-awaited Frozen 2 was released to mixed reviews, with some division over the sequel’s attempts to deepen the series' lore and clarify the origins of Elsa’s magic. However, despite boasting a more immersive story than the original Frozen, Frozen 2 didn’t answer every question that eager fans had about the franchise’s mythology and instead led to some new confusion amongst the franchise's fandom.
However, a Frozen prequel novel called Dangerous Secrets: The Story Of Iduna and Agnarr offers an answer to one of Frozen 2’s major mysteries, which is where the movie’s villain King Runeard’s distrust of magic came from in the first place. Late in the action of Frozen 2, viewers learn that Arendelle’s former ruler King Runeard, the duplicitous grandfather of Elsa and Anna, found magic to be inherently untrustworthy and dangerous. As a result of this prejudice, the king betrayed the welcoming Northuldra tribe and caused a rift that has endured through generations. However, Frozen 2 never explains how it is that King Runeard came to this dramatic, story-shaping anti-magic stance. However, Dangerous Secrets: The Story Of Iduna and Agnarr features a background section for King Runeard that explains that his wife (Agnarr’s mother Rita) was homesick and depressed at feeling like her husband's captive, thus indirectly leading to his hatred of magic.
Rita's overwhelming hopelessness, worsened by King Runeard’s uncaring attitude, led the despondent queen to ask Frozen’s trolls to wipe her memory of her family and allow her to return home without feeling guilty about abandoning her offspring. The trolls agreed to do so and Rita left King Runeard behind, ironically solidifying his self-fulfilling belief that the Northuldra tribe couldn’t be trusted. As a result, when Runeard discovered that his love Queen Rita had run away. he inevitably blamed magic at large rather than reflecting on his misgivings.
With Runeard being the kingdom of Arendelle’s unquestioned ruler (and boasting a good reputation right through to the events of Frozen 2), his whole kingdom followed suit and began to distrust and despise magic. This piece of vital backstory clarifies why Elsa felt her magic was so dangerous and abnormal, leading her to hide her abilities in the first Frozen. The missing piece of backstory also clarifies why Runeard had such an outsized paranoia of being betrayed, as his betrayal of the Northuldra tribe and his distrust of magic as an institution left the Frozen 2 villain certain he would be overthrown and dethroned by magical means, the tribe he misled, or both at once.