Story till mid game

Below may contain spoilers till mid game.

This game took me a month to reach the first boss(the one on horse) and I quited the game for several months because i couldn't beat the blaze bull. I picked it up again 2 days ago and started slowly progressing. Now I just beat Genichiro and started getting obsessed with the game as I'm getting better with parrying and dodging. This games started getting more fun instead of a torture to me. Therefore I would like to understand the story more, but I have so many questions. Im not sure if it's I missed something or my questions will be answered as I continue the game. So if it's the latter case please no spoilers.

• According to an iron code Sekiro's father gave him, sekiro needs to protect Lord Kuro at all cost: Who's Lord Kuro? Why I'm saving her?
• what's the reason genichiro took Lord Kuro at the beginning of the game?
• Before the boss fight of genichiro, Lord Kuro refused Genichiro, what was that?