A Rip Letter is a letter that allows non-Incubuses to Travel. To Rip somewhere with it, all you have to do is touch it while going anywhere in the Caster Tunnels. It is not an easy Cast and more of a status thing.
Ryan Duchannes received a Rip Letter with the words "H.T.V.T.", meaning "Hold to Virtually Teleport"; thinking it was sent by her sister as a friendly invitation to see Link's performance, when it was actually from Lennox Gates, Ryan took the letter and appeared at Sirene. Ryan described the Traveling experience as "like riding in a Ferrari".