Rurouni Kenshin: Meiji Kenkaku Romantan, Black Cat Recommendations
The two main characters go through similar changes in their lives. They both begin as assassins and eventually turn around to use their skills for the good of others.
both (kenshin and train) are trying to forget that they aer infamous assassins.
Fighting series about a former assassin who's sworn never to kill again. Both series handle the balance between the 'starting a new life with new friends' and 'what to do when the past catches up with you' elements similarly.
Both are tales of radically changed legendary assassins and their quirky companions as they fight their past lives. Although time periods and weaponry are radically different, the feel and general overall tone are shared between the two. As always, when they enter their "past" mindsets to fight is when the real fun begins.
Very similar main character and plot in some instances. The protagonists have very similar circumstances and are both former elite assassins who've had a change of heart, and no longer want to kill. Eventually, they also have to deal with their past. Kenshin is obviously in a different era with swords, ninjas, and samurai, while Black Cat is for the most part, modern day.
Both involves a character, who was an assassin in the past, who avoid killing no matter what. It feature rather similar drawing style too.
Both protagonists used to kill people, but have taken a personal vow to protect people to make up for what they've done in the past. Granted, Train was an assassin and Kenshin was a samurai, and they have different reason for no longer wanting to kill people. However, there are aspects of both manga that I feel will appeal to the same kind of people.