SUPER MEGA SPOILERS! Watch at your own risk!

Before you do this battle, make sure you've rescued all the villagers, or else you'll get the bad ending. Otherwise, once you've rescued them all, do this fight to continue the game.

Well, here's the boss fight with Albus, he is very hard until you figure out how do deal with him. Well, he has a bunch of different attacks, jumping is a good way to dodge them but that will often provoke him to use his flaming kick attack. Rather, the easiest way is to stay ducked and slide past him; unlike other enemies Albus doesn't deal contact damage, just don't stay inside his sprite or you'll get flame kicked in the face.

And make sure you get the Acerbatus Glyph from him, if you're using the sliding strategy you should be behind him often enough to absorb it quickly enough in the battle, this lets you use Albus's own Star Shot attack.

Vol Umbra is great here, nothing else can do as much damage, Albus is weak to darkness plus with all the Black Drops I found it takes him out really quick, though of course the time I tried to get the medal I didn't drink them...

Vol Umbra and Vol Luminatio make a pretty sick Glyph Union. Seriously, it costs 50 hearts but does crazy damage, it's a shame it killed Albus so quick since his battle theme is pretty sweet.

Also, don't ever use the Dominus Glyph Union, it will kill you!