Song of the Unslakable Blade - Castlevania: Harmony of Despair
This stage is filled with traps that can easily endanger your HP before even reaching the boss. Another problem is that Death himself will keep harassing you by releasing a volley of small scythes whenever he follows you. You can deflect these scythes with your weapon or just protect yourself with your shield. You can attack Death even if he's transparent. If you managed to deal enough damage to him, he'll retreat back to his room and stop harassing you.
It will be hard to explore the entire area alone. The path to the boss however, is straightforward so you can just make a run for it.
1.This is one of the spots to deal with Death early on. There will be times that if you stay here, he'll just come right at you and will attempt to release his scythe swarm. Since he's transparent, don't mind mind going through him and attack him. I've repelled him three times using this method.
2.To reach the third tower to the east, you need to jump on the grandfather clock and land on the minute-hand of the large clock. You can then use it as a foothold to reach the moving platform to reach the teleporter mirror that will take you to the other tower.
3.(Hidden Item) Stand on this spot and press UP for the secret item to appear from the right side of the screen (red arrow in the map above). You may want to switch your map view so you can see the whole map. This item may be a lot difficult to acquire if you're playing solo. The sole reason is that the item (Vic Viper) will fly away fast upon activation and its almost impossible to catch up with it, unless you have the Mercury Boots. Having a second player waiting on the rooftop will be a great way of catching it though the person that activated it won't get the item instead. See the video here. In case you missed catching this hidden item, you need to do the chapter again to catch it.
This boss has predictable attacks that can easily be avoided or predicted. If you're playing as Alucard, his Mist Form skill will play a great role in surviving most of the boss' attacks. Death is most vulnerable during these two attacks: when he's releasing a swarm of scythes and when he releases three souls that will encircle him. When you see him pointing his palm towards you, quickly dash so you can position yourself between him and the scythe swarm or better yet, behind him. As for the second attack, you can stick close and quickly move inside the soul circle. You should be able to score free hits while the souls are active. Please refer to the video below for more details about his attacks.
Boss Battle: Death