I'm trying to find a fantasy series that I read a few years ago, and I can't seem to find any trace of it in any of my records or collection. I've looked through similarly asked questions on several websites and found novel series like Runelords, Runemarks, and several other fantasy novels that have piqued my interest. However, none of them were the novel I read. I can't remember the name or title, but I can remember these details:
1) The main characters were a boy and a girl, an older brother and younger sister. The sister went to the academy to learn magic, while the brother trained to be a warrior. Over the course of the story she becomes adept at magic and he becomes a "swordsinger," an elite warrior who sings spells while fighting to activate the rune spells in their armor and swords.
2) Magic was mainly centered around runes. They were placed on or in things, and then activated with this spirit liquid stuff that was very rare and very expensive. This also means magic was restricted to a certain extent, an expensive luxury.
3) There were several wars, or rather several battles of some kind of major war. I can't remember all the details of the fighting, but there were a lot of tactics and strategy involved. Not quite Game of Thrones level deep, but the writer wasn't completely ignorant of military writing. The brother, as one of the few sword singers left after several battles, worked his way up through the ranks until he was basically commanding the whole army.
4) The main bad guys, aside from the mess of all the warfare in the foreground, were these super magical deity like characters that had been sealed away in another dimension a long time before. The female main character ends up on a quest to stop their resurrection, but I don't know if she does. I didn't get that far in the series.
If anyone can help me remember the name of this series, I would greatly appreciate it.