Tensei Shitara Ore ga Heroine de Aitsu ga Yuusha datta

High schooler Azumi Keito's life takes a surreal turn when a stray truck accident doesn't end things—instead, he wakes in another world...as its heroine. Even more baffling? His longtime friend Taiga has been reborn as the world's hero. With the promise of returning home tied to defeating the Demon King, the two must navigate new bodies, evolving roles, and a landscape rife with magic and monsters. It's a journey filled with swordplay, self-discovery, and the delightfully awkward realization that roles and relationships can be wonderfully mutable.
(Source: Titan Manga, edited)