The Ruthless Commander and his Reincarnated Warhorse

A horse that reincarnated from modern Japan into another world has found peace living freely in the forest, enjoying the simple pleasures of his new equine life. His tranquility is shattered when he's forcibly taken by Commander Felix, a stern military officer whose life he once saved, to serve as a personal battle horse. Now caught between his desire for freedom and the demands of military life, the horse must navigate his complex relationship with the demanding commander while keeping his unusual origins a secret in this fantasy world. (Source: Shodensha, translated)