The Stormlight Archives (first book is The Way of Kings.) - It's an awesome epic fantasy series with strong character's and a really interesting world and magic system. It's really interesting to watch the plot be affected by the character's actions and the character's developement being affected by the plot.
In this book, a war is being raged on a broken land known as the Shattered Plains, being fought between a race known as the Parshendi and a human country, the Alethi. Kaladin, an apprentice surgeon who traded saving the lives of many for one has found himself in the midst of this war as a slave. Shallan, naive and sheltered, seeks to enter an apprenticeship with famous scholar in a desperate attempt to save her family. Dalinar, an old warlord and brother of a late king, sifts through an old text as he is plaugued by visions of the past and worries of the future.
It delves into interesting themes such as what is "right" and "wrong" and how events and different mindsets can differ your outlook on life. I'm a big fan of books which stray into morally gray territory, so this series is no different.
Plus, it has some nice lore. The only issue is it might be a bit difficult to get your hands on since it's not the most well-known book series. Still really good and I reccomend you give it a shot if you're into this kinda stuff.