Personal tips for Chapter 4 mid boss (not Alexei). It is a big fat monster you fight on a bridge.
* Stay in front of him and lure him to only use his one handed slam, one hand grab, or the howling blast.
* When it is going to howl, he will move 2 step in front. So when you see that, dash to the right twice and while he is howling, put a nice combo onto his hands. If you got hit by his howling blast, you are dead. It is a one-shot death (Master Ninja difficulty).
* If he raises his hands in a horizontal direction, he is going for the one hand grab and try to dash away from it. If you got grab, you might lose 80% of your health.
* A good time to hit him would be when he does the one hand slam. Everytime he does it, the attack can either be blocked (yes it is blockable despite the size of his arm) and can be avoided (dash). It would be better to dash away and unleash a combo on his hand since the recovery from a dash is faster than a block.
* Remember to remain in a place in front of the monster. Do not ever go underneath it to slash its legs. He will do the whole body slam which is hard to avoid and 2 hit from it and you're dead.
Hope this helps whoever is going through the game. It is possible to beat this boss without a single drop of health point. I can beat it 30% of the time so i guess the above tips is considered to be quite feasible judging by how difficult Master Ninja is.
Anyway, do remember is that after the boss fight, you will have to deal with yellow winged fiends (a lot of em) and there is only a save point after your defeated all of them and a couple of IS ninjas. If you die along the way, it is back to the boss