After getting Dracula's Nail in Bodley Mansion, you should make your way to Laruba Mansion.
Get the Flame Whip
If you bought the Morning Star in the town of Ondol, you will be able to get the Flame Whip, which is the strongest whip in the game. To get it, go left from Bodley Mansion until you reach a lake. Equip the Red Crystal, then kneel. Soon a path will appear below the lake. Go leftward down the path, ignoring the stairs.
To the left, you will find Uta Path, a watery cave full of Skeletons and floating Skulls. Go to the left. Jump onto the single block, then walk off the left side to go back to ground level. Go to the left and jump across the moving platforms. There is a wall at the end, but you can break it with Holy Water, or with your Whip if you equip Dracula's Nail.
Go through where the wall was, and talk to the Gypsy there to get your Morning Star turned into the Flame Whip.
Go to the Mansion
Go to the right from there, and jump up the platforms until you reach a wall. Use Holy Water on it, or equip Dracula's Nail and whip it. Then jump along the path to the left. Go to the bottom-left of the area (there is nothing of interest in the upper part of Uta Path), and go to the left to exit. You will now be in the Devious Woods.
Go to the left, fighting floating Skulls and a Firebug, then jump across the floating platforms, making sure to jump when the block is almost at the top of its path. Keep going to the left and you'll reach Joma Marsh.
Hopefully you have some Laurels. Use a Laurel and go leftward through the poison swamp. When the Laurel is in effect, the enemies can't hurt you, so don't bother to stop and whip them. Just keep going to the left, using more Laurels if necessary, and eventually you will reach Laruba Mansion.