I would say sekiro has no grind unless you want to max out the skill tree. There is only one skill you really need which is mikiri counter which is the first or second skill. In sekiro the way you increase your strength is by killing bosses, every boss you kill drops a memory that you use to strengthen yourself. You increase your health by collecting prayer beads you will find a lot naturally just make sure you kill mini bosses (mobs with the red dot under there health)