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 Reverse Wall + Reverse Library
Castlevania: Symphony of the Night Reverse Wall + Reverse Library
Traverse the outer wall upwards. Make sure to check out the warp room.
Once you find the door that leads to the Reverse Library, enter it.
Stay the upper route and head right, until you enter the librarian's quarters through a hole in the ground. Head left, and make your way into the study in the Reverse Library (where the save point is)
If you're having trouble with the Tin-Men, Holy Water is a good subweapon to use against them. It stops them in their tracks, and does a fair amount of damage.
Don't forget about the revolving bookcase.
Explore the entire study, even down to the gas grate.
Finish exploring the rest of the Long Library, and head back out to the Outer Wall.
Keep climbing to the top. Once you get there, head right, and get ready to fight The Creature.
The Creature has two main attacks. If you're far away from him, he'll start rolling around the Battlefield. Jump over him, and slash like so.
The easiest method to use to defeat The Creature is to exploit his other attack Cycle. If you stand near him, he'll raise his hammer and try to smash it on you. Stand next to The Creature, attack him, then dash away from him (TRIANGLE) before he can smash you. Repeat until he's dead.
If you're in for a grind, you can keep killing the Paranthropus until it drops an item called "The Ring of Varda". It's an extremely powerful stat-booster, and if you get two, you'll become a force to be reckoned with.
"Finish traversing the entire Reverse Wall area. Don't forget about the secret wall you can smash here.