"Fairy Tail" chapter 491 promises a huge reveal as clues of Irene and Erza being mother and daughter are hinted in the early spoilers. Meanwhile, it seems like Zera, Mavis' imaginary friend, will be a major player in the upcoming chapters.
Early spoilers were revealed online courtesy of Manga Mint. In the leaked summary, Zera reveals that she is temporarily revived because Mavis' magic and thoughts were reset but once Mavis regains her memory, she will once again disappear.
Meanwhile, Irene's magic can basically oversee the whole kingdom of Fiore as she keeps track of everyone's actions. However, her attention was caught by someone with a scarlet hair, which is probably Erza Scarlet.
Before the chapter ends, Zera is seen delivering a telepathic message to every member of Fairy Tail to gather where majority of the members is. Also, she asked them to go back in the Guild as they need to protect the first Guild Master, who is currently facing Zeref.
As seen in the previous chapter, Irene was seen sitting in the throne of a certain castle. The image shows that she has a scar in her belly and the reason how she incurred the wound remains unexplained. Although it is unlikely that it was caused by childbirth, it can be assumed that someone made an attempt to kill her and her baby during that time.
Fans over at Reddit also came up with their own "Fairy Tail" chapter predictions and they are also positive that Erza and Irene's backstory will be revealed soon. This will also explain how Erza became an orphan and it is expected to be a dramatic reunion.
As a brief refresher of the previous chapter, the effects of Irene's magic were revealed and apparently, it rearranged the whole kingdom of Fiore. Everyone was dumbfounded with what happened and majority of the Fairy Tail members found themselves right beside the Alvarez Empire army. Meanwhile, it seems like Brandish and August finally made amends after Mest mind-controlled the former in stabbing the most powerful member of the Spriggan 12.
Here is a recap of the previous chapter.