Manga Rain (Sumikawa Megumi)

From Storm in Heaven:
The continent Murgenia, where they master swordsmanship and magic:
The small country Sunkwoll is in a tight spot because it's under attack of the great country Zarmine. But the general, Rain, who's reputed to be an exceptionally gifted swordsman, is against the war and won't enter the battle. But how is one supposed to wage a war like this anyway?
Based on the light novel series with the same name.