VANCOUVER, British Columbia — Most comic book heroes have an origin story. Here is Roberto Aguirre-Sacasa’s: He was 8 years old. He was in the supermarket. Next to the register he saw an Archie Comics double digest. He begged his mom to buy it for him. “I kind of never let the Archies go,” he said.

Aguirre-Sacasa, 46, “the good middle age,” he calls it, was speaking in a suite at the Fairmont hotel here. He lives in Los Angeles with his husband and a dog named Ms. Molly, but every week he flies to Vancouver where the CW’s “Riverdale,” now in its third season, and Netflix’s “Chilling Adventures of Sabrina,” which began streaming its first season Oct. 26, both shoot. He’s the showrunner for both, corollaries to his role as the chief creative officer of Archie Comics.

That he’s a (very) senior executive for a company that once sent him a strongly worded cease-and-desist letter (in his 20s, he wrote “Archie’s Weird Fantasy,” a play in which Archie meets up with the murderers Leopold and Loeb and is later revealed as gay, and it’s unclear which was the bigger problem) is just whipped cream on the malted.

With “Riverdale” and “Sabrina,” Aguirre-Sacasa has become an auteur of moody, sexy teen angst. He is a John Hughes for a darker, more cynical, way more libidinous age. When I asked him if “Riverdale” was a thirsty show, he laughed and said: “Big time. Biiiig time. Big time.”