If you're looking for manga similar to Kanako's Life as an Assassin, you might like these titles.
A girl and her mechanical guardian are living in a world where both humankind and nature has been abandoned. Even if the world around them is dark, there will be light if the both of them are together. This is the tale of a heart filled cyber punk manga.
Mayuri-chan likes to tease her childhood friend, but she can't take it if he tries anything back!