Earthen Peak (2)

From there, climb the ramp again and take the ladder this time without exiting to the balcony. Ignore the path to the right since it only leads to a deadend with an enemy. Go the left instead and follow the path. There are a couple of sorceresses guarding the path. You can destroy the poison urns beside them poison them and just stay out of their line of fire if you want to avoid damage.

The stairs to the left leads to the boss area; but before going there, it will be a good idea to explore first. Be careful of the sorceress and warden on the ledge to your right; take them out and continue along the stairs. The room to the right has a lot of poison urns.

This room has a chest, a corpse and Pharros contraption. Loot the Small Smooth and Silky Stone from the corpse but do not open the chest immediately. The chest is a mimic so don't open it but quickly attack it instead. Make sure to defeat it before it opens. Loot the Dark Gauntlets and Work Hook from it.

The pharros contraption will only spew poison so ignore it. Leave the room and go upstairs where you'll find an invader. Defeat him and go upstairs. Turn to the left and keep interacting with the wall until a secret door opens with a chest inside. Open it to get a Petrified Something.

There's also a secret door to the right that has a very convenient bonfire. (Thanks to Sylph_Blade for this tip and screenshots!)

Go downstairs this time and defeat the two wardens guarding the boss area. Loot the skeleton beside the stairs to get a Poison Stone. Now you're carrying a lot of souls here, you can go back to Majula and spend it to level up or just purchase some new consumables.

If you're also human, you can summon Jester Thomas from a summon sign right beside the stairs. The next boss is weak against fire so make the necessary preparations.

Boss: Mytha, the Baneful Queen

Since you've set fire to the windmill blades found outside the central bonfire, the boss area is now free of poison. If you have summoned Jester, you'll immediately notice that he is a potent sorcerer. His fire attacks can deal heavy damage against Mytha, as long as you tank her. You can also go on an offensive if you have a fire-enchanted weapon or can use pyromancy spells as well.

A shield with 100% damage reduction and high stability can help in tanking Mytha and letting your phantom ally do the job. If you're ranged attacker, Mytha has a lot of openings after her attacks and you have to use those openings to either attack or heal. Beware when she throws her decapitated head; it will release an explosive energy shortly. Don't stay anywhere near it after that as her body will lunge towards it to retrieve it. She can also cast magic attacks if you're always keeping your distance. Staying close to her while circling around her will prompt her to continue using her melee attacks.

Avoid using slow weapons unless you're timing is impeccable. Mytha's spear can close the distance quickly and can even hit you even when you're rolling. Mytha's attack patterns are fixed and can be easily anticipated. The main challenge however is how quickly and perfectly you'll react.

Mythusa

After defeating her, ride the elevator and you should be able to reach the next area.