By far this has been the hardest boss, and cheapest. I didn’t really clock it, I’d say it was around 5 hours total, maybe more, over the course of three days. This was an annoying mission overall, in part due to the fact that you can fall into the water and drown, which carries over to the actual boss fight. Like most boss fights, Umi-bozu is a damage sponge. He’s also equipped with an attack that could kill you instantly, but at least it’s telegraphed enough.
Perhaps the most infuriating thing about this boss were the mini blobs that accompany it. They pester you, ruin your targeting, distract you from the boss’s deadly attacks and could cause enough damage to kill you. I read up on this boss and learned that lighting the bonfires spread throughout the map is key to making the fight easier. Each bonfire you light equals one less mini-blob to worry about during the boss fight. I believe there are three bonfires total and I managed to find and light two, but it made things significantly easier having to deal with only one mini-blob instead of two. If you watched the video all the way through the end, you’ll know that I was also extremely lucky to have defeated this boss. It managed to hit me one last time, bringing my health down to almost nothing, before I instinctively swung my weapon back, which miraculously connected and was enough to finish off this boss.
UPDATE: After giving it some thought I’ve come to the conclusion that this wasn’t a very cheap boss after all, if at all it was. At the very beginning of the mission the game tells you to light bonfires (with one conveniently placed near the starting point) to ward off evil spirits or something to that extent. I lit the one that the game handed to me on a silver platter and didn’t bother to look for other bonfires after that. The resulting frustration was entirely my fault. When a game like Nioh gives you clues or more accurately, specific orders to do something as was the case with the bonfires, it is in your best interest to take it seriously, which I failed to do. Lesson learned!