Hello, Today's pick is the shounen action adventure manga "Samurai Deeper Kyou".
The plot of this manga is that in 1604 a female body hunter Shiina Yuuya mistakes medicine seller Mibu Kyoushiro for the legendary wanted man "Onime-no-Kyo". But she still captures him after realising that he is just a medicine seller because he is wanted for running off without paying for a meal.
Soon after that, they are cornered by a criminal and Kyoushiro eyes turn deep red and he transforms into the legendary "Onime-no-Kyo".
It seems that Kyoushiro and Kyou share the same body, and now Shiina and Kyoushiro/Kyou travel together. Kyoushiro in search of is memories, Shiina in search of her older brother killer and Kyou in search of is body sealed somewhere.

Description:

At the dawn of the 17th century, at the end of the era of civil wars, in a world of chaos, the epic Battle of Sekigahara was joined.
One man emerged from the largest battle ever fought on Japanese soil; a terrible warrior of unspeakable power, he was nicknamed 'the unconquerable.'
Kyoshiro is a peaceful medicine peddler who harbors the soul of an assassin. He accompanies a young bounty hunter across Japan in search of a murderer and on a quest to discover the terrible secret of his own identity.