She writes fantasy but also noted for her Lovecraftian (Cthulhu) works. Her work covers many genres; fantasy, horror, mystery, etc...

Vols.1-3, "The Leopard Mask" "Warrior in the Wilderness" and "The Battle of Nospherus" have come out in the USA.
Vertical,Inc., who is publishing Japanese fiction, will produce the first five volumes. A contract for 5 titles is a safe enough judgement considering the quality of later sequels. Earlier titles are OK (around 20 volumes)... but later ones? Silence.

This is one of the best known heroic fantasy (and longest) series in Japan (maybe even in the world from the standpoint of its titles alone...) In the end, this series will consist of 100 volumes (!) and a dozen or more of side story titles. So far, over 90 books including side stories, are published.
OK, it's long, then how's its quality? One might ask that. Well, the story just continues and continues, with a bunch of protagonist. I can say the characters are well realized (who can't? with so many books to describe them...). As I said, I can recommend earlier titles (do not go beyond vol. 16) but later works are sometimes not worth reading. As a longest series (Guinness class?) and considering its historical (in view of Japanese heroic fantasy) importance, you might want to try the translations.... It has some interesting developments.
I liked the earlier part of the series myself and still buy the books when a new title comes up. But as a whole, the quality varies drastically.
(I stopped purchasing this series as of 2004. I thought to complete the whole titles as the author said the target was 100 but now, she is saying this will not end with volume 100th. Well, well, dear author, I cannot follow you anymore. Bye bye and good luck.)
One of the main (this is the leading character) protagonists is a man with a head of panther. There is a lot of politics, intrigues, rescue, quest, magic, mystery and so on. Sometimes, her style centers on monologue like musing and it lags lags and lags! ... She has enthusiastic bunch of Guin fans and her new title often gets best seller in bookshops. (A wonder if one considers its quality.) Compared to a lot of other fantasy, this work stands out well enough for better or for worse.

Each volume has an English title along with (of course,) Japanese one. I've listed that English title and the original Japanese title transliteration. I think the English titles convey the meaning of original ones fairly well.

Here it goes! nearly 100 volumes already...