This creature can be found at Tul's Breachstone

How to create Spectre bank and what for you would need it

Sometimes your Spectres may die so you have to raise new ones
Everytime you use Desecrate - you refresh the list of creatures which would be spawned
(each map contains list of creatures, might include additional conqueror packs if the map is under influence)
For permanent access to chosen spectre corpses you should do next things :
Move to map with desired creatures
Use Desecrate to spawn corpses
(Hold 'A' , mouse over the corpses and use Raise Spectre when you find desired corpse
Remove Spell Echo if its equipped to prevent double cast)
Move to hideout and use Desecrate
Switch back to Witch u have just created
Use desecrate and quit
Create new character > Choose 'PvP only' to get level 28 character, which
is the minimum for Raise Spectre and logs directly into your hideout
Reset all passives and path to Death Attunement including str/dex nodes
Take Desecrate and Raise Spectre from stash tab and insert them into any sockets
Switch to main character
Use your main character to buy Desecrate and Raise Spectre ( Lilly Roth, A6 )
(Gems must be of the first level)
Move them to stash tab
Now your PvP-only Witch has fixed list of creatures spawned by desecrate
Once you need to respawn died spectres - Turn to 'Pvp-only' Witch > use desecrate >>> switch to main character, move to hideout and press desecrate to gain desired corpses
1
2
3

What Spectres we will be using :
Move to Ashen Fields (Act7) and summon
2 x Carnage Chieftain for Frenzy Charge generation
and 1 x Host Chieftain for Power Charge generation
(Use Desecrate, Hold 'A' , and select the correct corpse)

The 4th should be They of Tul (Perfect at Blight maps/Simulacrum)
It casts snowstorm which protects you
You take less damage and have a chance to dodge while in it
(quality doesn't matter)
*Brown text has picks on hover/links on click
Animate Guardian Guide
I would not recommend to use AG before the gem reaches lvl 20
Your character's helmet should contain '+1-3 to Level of Socketed Minion Gems' with next gem setup :
Animate Guardian
Raise Spectre
Minion Life

Blood Magic
Blood Magic would allow your spectres to non-stop cast their buffs in any situation
All picks contain links on click
To equip the items move to blood aqueduct or any other area, drop the items on the ground and hover over them by holding AG hotkey
If you want to upgrade the gear - repeat it with new items
(Old gear will be removed)
If the AG dies - you lose the gear
Animate Guardian Guide
I would not recommend to use AG before the gem reaches lvl 20
Your character's helmet should contain '+1-3 to Level of Socketed Minion Gems' with next gem setup :
Animate Guardian
Raise Spectre
Minion Life

Blood Magic
Blood Magic would allow your spectres to non-stop cast their buffs in any situation
All picks contain links on click
To equip the items move to blood aqueduct or any other area, drop the items on the ground and hover over them by holding AG hotkey
If you want to upgrade the gear - repeat it with new items
(Old gear will be removed)
If the AG dies - you lose the gear