Days of the Heartfly (TLCP April fools book :3)

One day, Yuma has woken up to see herself as a Ruby heart gem that has the ability to fly! But then, it wouldn't be surprising for her to suddenly wonder why not only she has been turned into an object, but it goes the same for other letters in the world too!

Who could have started this letter-into-object madness? Find out with her in this book!1!1!