Moria’s recent reintroduction can only mean one of two things:
1-He dies and his devil fruit is stolen by Blackbeard
2-He is set to join Wano to confront Kaido
Why would Oda reintroduce a character only to kill him off screen? In my opinion Miora reluctantly agrees to go in Wano. His goal will be to defeat Kaido first and then Blackbeard. In a sense, the same as for Luffy.
Moria’s whole reason for stealing Luffy’s shadow was to take revenge on Kaido for killing his entire crew.
So Moria’s sad backstory will be shown and he will eventually join forces with Luffy.
*Theory by HikenNoAsxce