When you're exploring Pangzhen in Phantom Blade Zero, you'll eventually come to a roadblock when you visit the Green Serpent House, as you'll be required to enter the Mirage Estate to continue the main quest. This will require you to collect specific items, visit new regions, and fight a selection of Warden bosses.
This can be a little hard to get your head around, especially if you don't know how to access these areas or lack the prerequisites needed to track them down. So, allow us to make things easier for you and show you exactly how to open that pesky Serpent Door.
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Prerequisites


Before you even consider going off in search of these items needed to unlock the Mirage Estate, there are a few things you should do ahead of time to make sure you don't hit any snags along the way.
Firstly, we would suggest that you find a way to access the Lake Miegu region, which is accessed by heading to the Pangzhen Docks and interacting with the Motorized Boat at the docks, which will then allow you to sail around the lake and explore to your heart's content.
Then, you'll need certain Phantom Edges to access Serpent Houses located in earlier regions. Primarily, you'll need the Flaming Mane, which is accessed by first beating the Maskbound Lion Dance Grandmaster boss, and then taking this item to the Jingyang Hall, where it can be upgraded to the Flaming Mane.
Red Serpent House - Serpent Tongue


Firstly, on your quest to collect all these items, we would suggest heading to the Crimson Forest, where you will be able to use the Flaming Mane on the brambles nearest to the Red Serpent House Bell. Then, once inside, you can collect the Red Serpent Tongue and the Loong Emblem (yin).
Black Serpent House - Serpent Fang


Your second stop is in the Village Of Lu, where you'll find the Yellow Serpent House at the bell of the same name. It's the same deal as before, as you'll need to use your Flaming Mane to clear the brambles nearby, and then you can collect the Black Serpent Fang and the Loong Emblem (yang). The reason you need to visit these two before the White Serpent House is that the two Loong Emblem pieces combine to form the Loong Emblem Key.
White Serpent House - Serpent Eye


With all you need in hand, you can head to the Pangzhen Docks and get in your motorboat to take to the water. You'll likely have a fully fogged map of the area at this point, so to give you some idea of where you're going. You'll want to head right out into the middle of the lake, where you'll find a series of islands, and the White Serpent House is located on the third island along.
Once here, you'll fight some enemies and then come to the door where you can use the Loong Emblem Key, and awaiting you on the other side is a boss, Heartpiercer, Elite Shadow Warden. Here is the suggested build and a few helpful tips to beat this guy:

Suggested Build
- Weapon: Baishan Stormswords
- Secondary Weapon: Jagged Steel
- Phantom Edge: Fire Meteor
- Accessories: Nameless Thumb Ring, Arrowward, Reflex Device, Battle Wraps
- Medicines: Healing Gourd, Longevity Tonic
Tips To Beat Heartpiercer
- When they throw their Sundering Dual Blades at you, it's best to hold block or parry them if you're confident, as this will return these attacks to sender.
- Watch out for their red glowing prompt, as missing this will usually lead to getting hit with projectiles that often drain about 50% of your HP
- Manage your Sha-Chi carefully during exchanges, as their Sha-Chi draining attack followed by a spin attack can be devastating if you're running low and can't evade.
- Stick close to this boss where possible, as they are much more deadly at range than they are at arm's length.
For defeating this boss, you will receive the Sundering Dual Axes. After defeating this boss, you can then collect the White Serpent Eye, and then head back to Pangzhen.
Entering The Mirage Estate

Then comes the final step, as you head back to Pangzhen and, more specifically, head back to the Green Serpent House. You'll want to interact with the Snake Door to the right of the NPC that upgrades your Medicines, and after slotting in each item, the door will open, granting you access to the Mirage Estate.
However, fair warning to you. From the moment you head to the Mirage Estate, a lot of your pending side quests will automatically fail, as this is a pivotal point of no return within the game. So we suggest visiting all other available regions and ticking off side content from your to-do list before committing to the Mirage Estate.