Hello, this is my first time writing a guide,if we can call this text a guide anyway lol, english is not my main lenguage so i may have alot of mistakes here
since i havent seen anywhere talking about a build like this i decided to share, i did it myself but if someone already posted elsewhere please give it credits to them.
Lets Start:
This build started with a normal blood boild build, but i was having trouble killing t5 heralds on p8 and baal/ ubers soo.. i decided to put 1 point into echo for test and well it was not that bad.. playing this way for a bit i found myself using more lvl 1 echo strike then max blood soo i tought,,. why not? i ended up, at least in my perspective having a really high speed clear build that can do everythingon p8 without a problem and i can never die, ( with the hc version even on disconect i dont die, the demons clear the screen)
I did ran alot of variants and ended up with this skill build
Demon tree
20 bind demon ( the demon is soo strong that he dont come even close to die, tanking p8 t5 herald with thorns and uber ancients on p8 without a problem)
20 demonic mastery ( 3 demons alot of damage and other buffs to our demon)
20 blood oath ( best skill in the game right now, how to skip it? this make i complete ignore any res needed
Chaos Tree
1 lethargy ( i can have this up to level 26 with 1 point only and its soo good there is no point in not using it to kill heralds and bosses
Eldritch tree
1 hex bane ( alot of extra magic damage and biggest point is reduce defense, this + lethagy helps alot merc and demon)
20 mirrored blades ( we want to max this for more blades being casted per cast)
all other points into echoing strike ( yes you read right, we dont max this)
About Gear:
while i do play with a bo bar and mostly p8 im faar away from been the best gear possible (i even need a reset to take off some str and put on life) and thats prove the point of this build dont really need more.
Helm: 2 warlock 20 fcr 2 sock with 1 protector the other slot is empty right now, probably will put an ist on it ( i dont really need anything else my ress even tought they are negative its not a problem, for HC version i run coa with protector and a 40 ed 9 str)
ammy - highlords ( i never really search if anything else is better, i already reach 125 fcr with this, and its cheap probably a good 2 15 would let me change weapon for the 169 mf eth tomb reaver i have but right now using it make me have only the 75 break point)
rings - bk ( both 3% for cheap and i just want skill and life
shield - spirity 35% ( well.. its spirty)
boots - here we have a few options i like to use war traveler since im doing chronicle but usually i run wraistep
belt - Arach ( fcr and skill)
gloves - Magefist or trang ( dont really matter for me
Weapon - well i run with and eth insight cv lvl 15 aura with 6 critical and 256 ed ( its my first one done this ladder and i kept it) here we have ALOT of options, i just like this one AND the one with tomb raver for mf ( on high damage version i have about 218 mf and with tomb shuld go around 390, but to reach the 125 with tomb i would need to change rings and ammy and i dont fell like needed, maybe i just need to find some gheeds and put an ist on the other sock shuld make me near 300 mf anyway)
offhand - mang song and a 2 warlock 3 demon bind blue book - this is just for the summon defiler and cast hex
inventory: i run 8 eldritch gcs plain ( yea you can have alot of more life then i do with lifers) and mf sc's torch and anni i have with 20 stats and thats it - i really wanna test a decent sunder charm but still didnt found one, i think the power with one will go way higher
merc: the basic pride lvl 16 conc eth coh and cure with might, nothing special
demon: i know there is alot of discussion about best demon and aura, i just happen to grab a tz 96 p8 a5 lancer with fana and liked it, i really dont know why but i fell like it have some kind of holy aura as well the proc on the curse is soo fast every teleport that i mostly dont note diference from hephasto with holy something, but again thats just my setup fell free to use whatever you like.
gameplay
here is nothing special, just summon 2 defiller use hex and go telestomp anything
my stats are like this

Info bonus,
if you really want a full power of this build, for a longer session like full game tz or something you can even do this for more demon power
swap your gear for:
3 demon ammy
3 demon helm
9 demon gcs
wraith boots with demon skills
put offhand and make a new game, since the demon is resummoned with the skill level when you enter the game you just need to have high level when enter then i switch back to normal setup, but seriusly? i dont remember last time i did it, normal setup just do the job so this is just a bonus if you really want max power on this build
well sorry for the wall of text, i tried to summarise as much as possible
hope this can give some fun to someone else i really like this version
ps: enjoy while it can the nerf is mostly going to happen anyway
thanks!