Fantasy story with a young female protagonist and an ageless wizard

Question

I am searching for a series of young adult books I read approximately 10 years ago (2010). They were from a library so I assume they can't have come out before 1990.

There are two protagonists: a young girl of around 13-16 and a wizard who is much older (50+).

As a consequence of a ritual performed at the beginning of the first book, the wizard looks permanently in his mid-twenties despite being much older. I think he binds his soul to a book, he may also be missing an arm.

At some point, the girl uses the book to enact another ritual which ages her about 10 years. She then attempts to romantically pursue the wizard. The ritual makes use of a lot of blood.

There is a villain who wears the pelt of a wolf and is able to shapeshift into a wolf. In one of the later books, he wears the skin of a person who can shapeshift into anything and gains this power.

Answer 1

This is James Clemens' The Banned and The Banished series. The first book is Wit'ch Fire

The one armed character is El'ril. He is not a wizard, though he is immortal thanks to a spell cast in the opening chapter by his Brother. He is a travelling juggler at the start of the story proper and is over 500.

El'ril is the protector of a book, and it is the book that keeps him alive, though the arm was lost in a different spell/ritual to lock the book away.

The young girl is Elena Mornin'stal. The eponymous Wit'ch of the 5 books. She has her first period in her introduction chapter. She gets aged up somewhere around book 3, though the blood ritual your thinking of may be a different part of the story where blood is used to break the connection between a monster and the land so it can be killed.

The villain is a bit of a spoiler

One of the girl's companions is tortured and turned by a powerful minion of the Big Bad. This turning buffs his innate magical gifts, adding a shapeshifting capability. He can turn into any animal that he uses the pelt of to cover his axe. His name is Kral and

The race of shapeshifers are the si'luran. The first two we meet are cursed brothers trapped in a single form, one a man the other a wolf.

The books were published between 1998 and 2003.