Starting with the Ending

As I noted in my previous post, I'm writing a new trilogy. Each book will be story of the quest for that character, but will include references to the other characters and some of their lessons learned along the way. So that means that each book has to end up in the same place. Regardless of how each main character gets there - and their paths will be different - they all have to get to the same place in the end, to finish the quest.
So, this weekend, I wrote the end of the trilogy from a generic perspective. How the quest will end. How magic will be restored. And how the three main characters come together to make that happen.
I'm going to take that same ending and incorporate it into each of the three novels. But change it, as well, as each of the final chapters - as with the first chapters - will be written as a first person narrative. Thus, we start and end each book inside the head of the character about whom the book is written - and whose quest is described in the book. This is a style taken from my fictional biographies, which are always written in first person.
(However, the interim chapters - however many they might be - will be written with an omniscient narrator, as I've done with all my previous fantasy novels. It think the combination is interesting - and makes the trilogy unique.)
Today, I took the generic ending I had written yesterday and tailored it for Hallas, the main character of the second of the three novels. So, now that final chapter lets us know how he was feeling during the pivotal climax. With a bit of a denouement, as well.
I'm still not sure if I'm going to write all three books concurrently. But it's sure starting to look that way.