Interesting premise. But not really a good fit for me.

Empire of Silence (2018) is first in the Sun Eater series.

The story is written as a first-person memoir told by Hadrian Marlowe, a man who is remembered by history both as a legendary hero who eradicated an alien threat and as a monster who destroyed a sun, killing billions of lives.

The Frame Narrative: An older, captive Hadrian looks back on his long life, attempting to explain the complex choices that led to his infamy. 

The Flight: To avoid a grim future engineered by his tyrannical father, Hadrian flees his aristocratic noble house.

The Fall: Stranded penniless on a backwater world, he is forced to live in the slums and eventually fight for survival as a gladiator. 

The Conflict: He becomes entangled in the political web of the Sollan Empire and the devastating, galaxy-wide war against the mysterious, predatory alien race known as the Cielcin