OPTIONAL: DARKROOT BASIN, THE HYDRA, AND DUSK
On your way back to the Undead Parish from the Darkroot Garden, you may notice a path to your left just before you hit the Parish. This leads to a series of downward slopes that takes you to the Darkroot Basin. Alternatively, you can reach the basin through the bottom of the tower where you fought Havel the Rock.
Once you reach a large, open area, you’ll spot several Crystal Golems and, more importantly, a massive, water-spewing Hydra. Clear out the golems by luring them away from the hydra, then get ready for a fight.
Equip the Rusted Iron Ring and a shield that has 100% physical resistance.
You’ll want to approach the Hydra from the left side of the basin, staying out of range of the very harmful projectiles for as long as possible. Eventually, you’ll have to make a break for the Hydra. Roll at the right time to avoid any projectiles. Once you’re in the water, the Hydra will start stop trying to shoot you and start trying to bite you. Simply block the bites and attack while the heads are still nearby. The Great Chaos Fireball Pyromancy works well, as does any high-damage, two-handed weapon.
As the number of heads reduces, it becomes easier to tell where each one will slam into the ground when the Hydra lunges forward. At this point, it’s just a matter of running over to the proper location and hitting the heads while they’re stationary. Be careful not to wander too far into the lake for there is a deadly drop off.
The Hydra drops a Dragon Scale and a Dusk Crown Ring, the latter of which “grants extra sorcery castings, but halves HP.”
We’re not done here yet. Quit the game and reload, then run left around the perimeter of the lake. Pass the waterfall and keep on going until you find a Golden Crystal Golem. Destroying this golem frees an NPC called Dusk of Oolacile. Answer yes to her question. She will then disappear. Run over to the shore from which you fought the Hydra and look for a summon sign near a rock.
This is Dusk’s sign, and if you summon her, she will offer to sell you some spells and a special catalyst. Finally, after speaking to Dusk, return to where you fought the Golden Crystal Golem to find the Antiquated Armor Set.