Warbreaker — Brandon Sanderson

T'TELIR, capital of Hallandren, is a colorful city by the sea where gaily dressed crowds bustle through sunny streets and worship heroes who have been reborn as gods. Ruled by the silent, mysterious God King, the pantheon is nourished by offerings of Breath, the life force that keeps them alive and youthful.

Exiled in Idris, the former royal family reluctantly betrothed a princess to the God King. Arriving in T'Telir, she finds both the city and the marriage are not at all what she expected. Her only ally is Lightsong, a god who is skeptical of his own divinity, who fears that war with Idris is inevitable.

Meanwhile, another new arrival in T'Telir, one who bears the sentient sword Nightblood, makes cunning plans based on the unique magic of Hallandren, which uses color to focus the power of Breath -- plans that, could change the world.