Does anyone remember a book that featured an otter. It was set in medieval times and all the characters were animals and he had to save the kingdom. And I just can't remember the name. Please help!
This sounds a bit like Alan Dean Foster's Spellsinger series, in which the anthropomorphic otter, Mudge, plays main friend and ally to the human protagonist. The series is notable for its anthropomorphized animal characters, and for its otherwise Western Medieval Fantasy characters being awash in substance use and abuse.
From my knowledge, this sounds a lot like the Redwall series, by Brian Jaques.
This series is about a group of anthropomorphic woodland animals living in an Abbey called Redwall, one of the more prevalent characters through the series is Martin, the warrior-mouse (he and his fathers before him have several books devoted to their adventures alone). These creatures are often under attack by "vermin" (depicted as rats, weasels, lizards and the like), but (fortunately for Redwall) these are often deterred by the Badgers that safeguard the coast in Salamandastron; a mountain fortress overlooking the sea.
As for Otters, there are a few in the series (that have their own tales*), such as
- Deyna was kidnapped while still very young, and raised by vermin, but later runs away to find the rest of his family at Redwall
- Mhera later becomes the new Abbess of Redwall, after she is reunited with her long lost brother (Deyna)
- Ruffgar Brookback joins a pair of Badgers in their quest to liberate Salamandastron
- Shogg who, along with a few other characters, escape slavery and set forth to find Redwall Abbey
- Bragoon grew up in Redwall, then set out to venture the surrounding lands
- Tiria Wildlough is visited by Martin the Warrior in a dream and given the task of liberating the otterclans of Green Isle
as well as a few others.
Perhaps the book is Nightpool by Shirley Rousseau Murphy? Apparently it is about a teenager who teams up with talking otters to "fight the Dark". I was looking up something else in Stack Exchange and found a similar request to what you're looking for at this question: What book features dragons, song-driven magic, and talking otters?