Question about Flagg & Roland

https://preview.redd.it/ksxi99p9jhng1.jpg?width=1252&format=pjpg&auto=webp&s=b7f551ac8dd42b404e24be922ebe4cde89238779

Hey guys, This is my updated Checklist. I am about 25% of the way through The Eyes of the Dragon and have a couple questions about Roland Deschain and Flagg's relationship/dynamic.

It is mainly Flagg vs Roland in TDT. In this book, it's also Flagg vs Roland (just not Roland D). Is this ever talked about? Is it some multiverse thing where every universe has a Flagg fighting a Roland? Is the Eyes of the Dragon the first chronoligical appearance of Flagg?

If possible, please answer with no spoilers! Thanks guys