"I'm the Evil Lord of an Intergalactic Empire!" is a science fiction manga series that blends elements of space opera, political intrigue, and dark comedy. The story centers on Liam Sera Banfield, a young noble who reincarnates into a futuristic interstellar empire after dying in his previous life. In his past life, Liam was an ordinary salaryman who harbored resentment toward corrupt authority figures. Upon reincarnating, he vows to live as an "evil lord," embracing the role of a ruthless and self-serving aristocrat to avoid the injustices he once endured.

Liam is born into the Banfield family, a minor noble house within the vast and oppressive Galactic Empire. The empire is a sprawling, hierarchical society rife with corruption, exploitation, and power struggles. Despite his initial intentions to act as a tyrant, Liam's actions often inadvertently benefit those around him, earning him a reputation as a benevolent and capable leader. His strategic mind, combined with his advanced knowledge from his previous life, allows him to navigate the complex political landscape of the empire, outmaneuvering rivals and consolidating power.

The narrative explores Liam's rise through the ranks of the empire, from a minor noble to a significant political and military figure. He gains control of a remote planet, transforming it into a thriving and prosperous territory through innovative policies and technological advancements. Along the way, he amasses a loyal following, including his childhood friend and maid, Marie, and his AI assistant, Tia, who aids him in managing his domain. Despite his self-proclaimed evil intentions, Liam's actions often align with justice and fairness, creating a paradoxical dynamic between his ambitions and his outcomes.

The series delves into themes of power, morality, and the consequences of one's actions. Liam's journey is marked by battles against rival nobles, alien threats, and internal conflicts within the empire. His interactions with other characters, such as the ambitious noblewoman Rosetta and the enigmatic Emperor, reveal the complexities of the empire's political structure and the moral ambiguities of wielding power. The story balances moments of humor and satire with darker undertones, reflecting the harsh realities of the empire's oppressive regime.

As the series progresses, Liam's influence grows, and he becomes increasingly entangled in the empire's larger conflicts. His decisions have far-reaching consequences, shaping the fate of entire planets and populations. The narrative maintains a focus on Liam's internal struggle between his desire to embody the archetype of an evil lord and the unintended positive impact of his actions. This tension drives the story forward, creating a compelling exploration of identity, ambition, and the nature of power in a vast and unforgiving universe.