Dark Souls II - How to beat Demon of Song Boss

One of the funnier looking bosses in Dark Souls series, Demon of Song is not that difficult to beat and execute. If you’re looking for tips on how to do it, though, look no further and read on.
First thing to notice is the Demon of Song’s shell - the monster uses its rough skin as a turtle shell armor of sorts, so the most practical, and well, the only way to incur any damage to it is when it comes out of his shell and shows its face. It’s not that shy though, so watch yourself.

The attacks that it uses when it is directly in front of you, are slow and are easy to avoid. Just as it comes out of his shell, he’ll try to strike you with its arms. Avoid Demon of Song’s attacks by jumping back or to the sides. You don’t have be that quick or alert to avoid its reach so just be prepared to jump in the right direction. After avoiding its attacks go ahead and strike him. If you’re quick enough, you’ll get two hits in him.

The little tidbit note, is that after you damage it, the Demon of Song hides inside his shell as fast as it can. You might have to wait a bit for the Demon of Song to come out, so just back out and be prepared for its attacks.

Another thing to take in consideration is that Demon of Song uses back-sweep attack, whenever you’re behind it, so try to stay in his front.

Demon of Soul uses hand sweep attacks when it is out of its shell. When Demon of Soul hides in its shell, it uses leap/body slam attacks, so be careful of those -- those are the hardest to avoid in terms of other Demon of Soul’s abilities effectiveness.

Don’t try to keep that big of a distance between yourself and Demon Soul, when it comes out of its shell. Demon Soul uses water ball attacks when you’re trying to keep your distance longer than you should, so just try to remember to strike it, when you see that it is coming out of its shell.

If you’re having some difficulty, another tip would be is to use lightning-based weapons -- Demon of Soul is quite weak to lightning attacks, yet he is resistant to fire and fire-based weapons.