This video was originally recorded on November 18, 2022 and edited on next day (19). It was intended to be premiered in few days later after the summoning video successfully published, but unfortunately couldn't get uploaded due to slow data connection and the start of hiatus until February 4, 2023.
The upcoming Legendary Hero summoning event that has Caeda & Nanna referred to was Mythic Embla & Legendary Veronica which sadly already skipped due to reason above on Twitlonger link.