Friedrich no Senjou - Shinku no Tensai Gunshi, Uso Kara Hajimeru Eiyuutan

Friedrich, a once-orphaned but brilliant young man, lived a quiet and peaceful life in a rural village. However, that peace was abruptly shattered by a raid from a band of thieves. While the villagers were consumed by despair, Friedrich stood apart—he stepped forward before the people and said, "I am the son of a hero. If you follow my plan, we will surely win!"

Noein is the son of a nobleman's father and his mistress. Despised by his family and servants, Noein grew up to be a twisted character, and after a 15 years of house arrest, he was evicted from the mansion. Instead of severing ties with his family, Noein was given an territory on the kingdom's frontier and the title of lord. But the frontier is nothing but a vast expanse of untamed forest. Determined to develop the frontier and become the happiest lord of all, Noein sets out to cultivate the land. With the golem manipulation magic he mastered while under house arrest and the advanced knowledge he acquired from books, he plows the wasteland and begins farming. The first two stages of the project go smoothly, but the most important thing is that there are no residents in the territory.

Slaine is a humble, provincial commoner in the small Kingdom of Hasenvalia… Or so he thinks until the day the entire royal family is wiped out in a palace fire and Slaine comes to learn he’s really the king’s illegitimate son. It's now falls on him to succeed the throne. Despite his lack of knowledge and experience, Slaine’s natural wits and dedication — plus the support of his aide-de-camp, Monica — allow him to excel against all odds. Between unsupportive nobles at home and hostile rulers abroad, Slaine already has his work cut out for him — and then, on the eve of his coronation, the great Empire of Galed declares war against Hasenvalia. Faced with such a frighteningly powerful foe, Slaine is forced to make a choice between fleeing into political exile or resisting invasion to the bitter end. Caught between the conflicting agendas of neighboring nations, this boy from a backwater town must learn how to grow into his crown. Witness the birth of a king!