Jonathan and Martha were going through a divorce so Martha took Rolfy to her parents place in Cleveland just below it blew up.
I wasn’t here for the booru so I don’t know the full story but from what I’ve read up the Fluffies created a methane cloud that ignited and blew up the city. Regardless of the actual reasons, Martha and Rolfy died in the explosion and Jonathan has been blaming Fluffies for their deaths ever since.
It was actually CuddilyBloodily who came up with the Cleveland idea with their Artwork. The Rolfy letter in the background gave me the idea to include a tragic backstory for Jonathan and add to his traumatic upbringing whilst staying true to the lore.