Phantom Blade Zero gives you quite a few accessories to pick from, which best suit your gameplay style. From universals like higher health, and damage reduction, there are specific ones like higher damage at higher health, to higher Sha-Chi depletion for enemy for a certain duration.
The Guardian Idol accessory firmly falls in the latter set – it gives a massive benefit that when combined with specific Phantom Edges. Getting this, though, requires you to collect 4 number of pieces in the Mandate Encampment region (like in case of the Medicine Pot in Huang Manor).
Here are the locations for all 4 fragments for the Guardian Idol accessory in Phantom Blade Zero
Guardian Idol Fragment: Head

The game makes the first piece pretty easy to collect, so that you can get on the hunt for others. This one is found right as you enter the Mandate Encampment Region. Make your way from the first bell – named after the region itself, and head in the opposite direction to the locked gate.
Ignore the grapple point that pops up on the right, and keep heading straight to arrive at an open area with a few enemies. Take them out, and you will see a shiny collectible in front of a well, head of a statue. This turns out to be the Guardian Idol Fragment: Head
Guardian Idol Fragment: Arm
Start from the Cliffside Walkway Overlook bell.

Ignore the ladder on its side, and take the wooden planks bridge across. Take a right and jump on to the enemies below to take them out. Cross the bridge and take out the ranged attackers here.

Here, in front of a red-lit shrine, will be the Guardian Idol Fragment: Arm
Guardian Idol Fragment: Torso
You then have to wait quite a while, and progress through the Mandate Encampment region before getting your hands on the next fragment.

When you arrive at the Behind The Encampment Waterfall bell, in front of you, and if you see on the map, will be a building with a hole on the roof. There are multiple ways of entering this building. You can take the climbable ledges, land on the roof, and use the hole to drop in. Or, you can use the ladder, and enter through the ground level.

Either ways, the end objective for us is to reach the ground floor of this building. At the very end is an orange shiny – which is the Guardian Idol Fragment: Torso. We have collected 3 fragments now, with 1 to go for the complete piece.
The building itself has another powerful accessory on the first floor, and an enemy on the roof who drops the Blackstone Shard – so do ensure that you touch these areas as well while you are here.
Guardian Idol Fragment: Leg

This one does not take much doing in terms of exploration, it is found right in a boss arena. Start from The Confinement bell, and defeat Wu Lengshuang, The Soft Sword. In the boss arena itself, there will be the final Guardian Idol Fragment.
Guardian Idol – When to use
Once you have collected all 4 fragments, these get removed from your inventory, and you get the complete Guardian Idol accessory.
The Guardian Idol, when equipped, gets Destruction-type Phantom Edges to consume 1 additional Remnant Spark, but, in return – deal 75% additional damage. This makes it best if you rely on your Phantom Edges to deal a lot of damage – you can use this at the beginning of a fight to set the tone. However, the best use is when the enemy is just about to go down, and, with that 1 single attack with the Guardian Idol equipped, deal massive damage.
