Shimotsuki Koushirou

Koshiro (コウシロウ, Koushirou) is the name of Roronoa Zoro's teacher and Kuina's father. He has his own Dojo near where Zoro grew up and he was the one who trained him. He is typically seen in flashbacks. However, in Chapter 440, he makes a brief appearance when another student of his asked if he was really Roronoa Zoro's teacher. He wished Zoro to go on ahead and fulfil his dream. It is implied he can also cut steel as he follows the method - Swordsman that can cut nothing can also cut steel and anything else they wish, he tries to teach this to Zoro as a child but it isn't until Zoro is 19 before he finally masters it.

Personaliy
Koshiro seems to apreciate talent as shown when he noted that as long as Zoro valued his Swordsmanship he wouldnt care if he had became a pirate. Also he showed that he belived that women was naturally weaker than males, as he showed sorrow when when kuina was born.

Ability's and powers
Its been heavily implied that he is a swordsman capable of cutting steel as shown when he was able to slash at a piece of paper without harming it, at least he is aware of the method of doing it.