If you want to leave Xander. a tip for writing this Castlevania: Symphony of the Night guide you can do so here.
Castlevania: Symphony of the Night Walkthrough Black Marble Gallery (Revisited)
Castlevania: Symphony of the Night Black Marble Gallery (Revisited)
Fight your way back to the clock tower area. You're in for a long haul.
When you enter the master clock room, the hands should point up, and the clock will strike thirteen times. You can go up to save, but don't take the elevator just yet-- we have to explore the rest of the level.
Make sure you explore the transition areas that are attatched to the Reverse Laboratory...
As well as the connecting area to the Reverse Entrance.
After you reach both areas, make sure to save in the save point (located to the right in this picture).
"Take a hard look at this map, and compare it to your own. This is the fully filled out Reverse Castle Map (minus a few blocks in the Reverse Catacombs and Anti-Chapel).
Alternatively, if you save and exit the game, you will see a percentage in your save file. If it's over or at 196%, you'll get the best ending.
Head all the way up, and then drop down into the main chamber.
Watch the cutscene with Shaft.
Shaft flies around the battlefield, attacking with his elemental orbs.
He can summon vertical/horizontal fire pillars,
Make his orbs bounce around the room,
And use eletrical beam attacks.
Attack Shaft's safety orb to damage him and eventually defeat him.