Yakuza Reincarnation Vol. 1  (English, Paperback, Natsuhara Takeshi)

An isekai like no other! When a tough old gangster wakes up in the body of a fantasy world princess, he decides to teach this new world the meaning of yakuza honor! Ryu may be getting on in his years, but the aging gangster is still hellbent on defending his turf when some young toughs ambush him and he wakes up in a fantasy world! Not only that, he's in the body of this world's princess! Is he the one that the ancient prophecy spoke of? Ryu might be out of place in this fantasy realm, but he may also be the only one who can save it!