This is “Dear Seanan” (a parody of Seanan McGuire’s song “Dear Gina,” based on Seanan’s October Daye series), performed at FilKONtario 23 by Erin and Rand Bellavia. Lyrics by Erin Bellavia and Merav Hoffman.
(submitted by @mysecretorigin)
(Source: https://www.youtube.com/)