Fantasy: Main character leads a militia in a world where there are 'magical rifts'. Finds out that he had been tricked into a rift in which time flowed backwards, so he became a baby again.

[Ford]

I read this book around 2004-2009.

The main character was a leader known for his cunning and tactics.
He has feelings of "deja vu" during the story and at the end of book one, finds out that he was tricked into a trap that turned him back into a baby.

Finds out his grandfather raised him again without letting him know about what happened.
Grandfather is overly hard the second time around to make sure he learns enough to avoid the same fate.

The world was fantasy based and you had to be wary of things like pocket dimensions and magic.

This was the first book of a possible trilogy (can't say for certain, since I was unable to remember it enough to look for the trilogy).

[Rainbowheart]

Does anything on the Aging Backwards list look familiar?

[David]

Hi, Ford.

Any details about the cover?

By your description of the MC, there is some kind of conflict, can you elaborate?

Is the MC the unique POV? Any other relevant character present?

[Ford]

I am unable to remember the cover, unfortunately.

I vaguely remember some hint of a larger conflict, but the book I read centered on the MC's actions as he patrolled around his town(?).

He was not part of the main conflict.