FE3H is Record of Grancrest War (Grancrest Senki), change my mind.
Together, Theo and Siluca gather a loyal group of allies—including the warrior —and begin a campaign to unify the warring factions. Theo's humble nature and straightforward honesty allow him to earn the respect of both soldiers and rival Lords. Grancrest Senki
Peace seemed possible during the wedding of and Marinne Kreische , which would have united the two major factions: the Fantasia Union and the Factory Alliance. However, the ceremony was struck by the Great Hall Tragedy , a massive convergence of Chaos that summoned a Demon Lord who murdered both archdukes, reigniting the war. The Unlikely Alliance FE3H is Record of Grancrest War (Grancrest Senki),