Embarking on Mercenary Life with a Catgirl in the Magical World

Mike, an exceptional mercenary from the era of post-apocalyptic wastelands, meets his end betrayed during a company escort mission. However, his soul crosses over into a world of swords and magic, inheriting the bloodline of giants, and begins anew on the path of a mercenary.
Cat Girl: Big guy, you're a good person.
Wizard: You're not as innocent as you look!
Tavern Landlady: Are you flirting with me?
Old Mercenary: Kid, you were born to be a mercenary!