Fantasy book about a brother who becomes a warrior and a sister who goes to magic school

Question

There was a book I read when I was in middle school. It is a brother/sister fantasy book.

The brother becomes a warrior, goes to a battle school, and then joins an elite group of soldiers that need to chant the runes on their armor in order for it to protect them.

The sister joins a magic school to then learn about the runes and I think goes off with a thief character introduce later. That detail is iffy.

There is a war that the brother goes to fight while the sister figures out why the runes aren't working and gets the runes back up in time for the conflict.

Any help at all is greatly appreciated

Answer 1

This sounds a lot like Epic Fantasy Novel with Runes where the answer provided was James Maxwell's Enchantress.

From the day Ella witnesses an enchanter using his talents to save her brother's life, she knows what she wants to be. But the elite Academy of Enchanters expects tuition fees and knowledge. Determined, Ella sells flowers and studies every book she can. Meanwhile her brother, Miro, dreams of becoming one of the world's finest swordsmen, wielding his nation’s powerful enchanted weapons in defense of his homeland.

A dark force rises in the east, conquering all in its path, and Miro leaves for the front. When the void Miro left is filled by Killian, a charming stranger from another land, Ella finds herself in love. But Killian has a secret, and Ella’s actions will determine the fate of her brother, her homeland, and the world.

Killian is the thief.

This review mentions the rune magic:

Welcome to a world divided into Houses,each having their own magic system: some are animators (bringing to life golems and other mechanical constructs), some elementalists (with power over elements of nature), some gardeners (with powers over plants). All magic is achieved by writing and chanting specific runes with a black deadly substance called essence. All essence is controlled by a Templar-priest and his acolytes who swore to protect and help the poor and needy. The specific runes giving magic to the different Houses are each gathered into a Lexicon, guarded by powerful sorcerers. The Lexicons have numbers inscribed on their covers and they seem to be all part of a powerful relic left by a race of superior beings called the Evermen, around which a new religion was founded. The story centers on 2 siblings, brother and sister, who become the high enchantress and warrior-general of House Altura, whose particular magic is endowing ordinary objects with strength, light, stealth. They grow and come into their powers in the middle of a war which threatens the very foundation of their world and the magic they came to rely on.

Found with novel brother sister warrior rune magic