I was a bit nervous because I know my adversary plays hard and has a full Tzeentch army.
I took biovores and harpy to to target his heralds and to masskill his horrors, toxgaunts to kill monstruous creatures, other gaunts to tarpit screamers and to claim objectives, flyrants and dakkafexes for the heavy wash-machine, zoanthropes for warp charges and synapse, tervigon for warp charge, synapse, objsec troop and more gaunts!
With MoA AND first turn in a relic game, I was likely to hold the relic and to alpha-strike the heralds, the screamers, the bloodthirster, the chariot… wait, what ? So many units to kill first! Actually I was more confident than the day before.

Tervigon and Venomtrhope in the centre, gaunts around, each dakkafex and Zoanthrope on each side ; I infiltrated the flyrants, the 30-gaunts blob and the gargoyles. Biovores stay away of the frontline but in synapse range. The toxgaunts stay behind to protect the rear or counter-attack.

On his side, his Bloodthirster hides in the middle, beyond the skullcrushers, his front unit are the nurglings, right side the vicious seekers (with herald), left side the famous screamers (with the disc herald), behind the plaguebearers who hold the aegis line with the quadgun, a unit of horrors with the other herald took place in a left-sided ruin, near the seekers. The other units stay in reserve.

I move ahead and hold the relic with gaunts. Gargoyles try to make a screen forward. FMC take off. I forget to spawn termagants.
Psychic phase : catalyst on the flyrants is denied but goes on from the zoanthrope to the gargoyles, I reduce the plaguebearer’s BS and WS to 1.
The right flyrant fires on the chariot but only does 2 HP off (WTF? I was supposed to eliminate it in one turn only!), the other one kills 2 screamers. The harpy kills 3 seekers and the herald (I like rerolling the scatter dice !), the biovores 7-8 horrors.
End of turn 1A:

He moves ahead also and prepares for assault. The herald on disc leaves the screamers. He fails his book test on the bloodthirster (which already has a 3+). He launched the portal and generate 6 daemonettes.
One unit of bloodletters is summoned (the useless daemons to summon?), other powers don’t work or are useless or whatever.
The warp storm doesn’t affect any unit. Actually it almost never didn’t so I won’t talk about except for the unique case something happened.
The chariot kills a few gaunts and gargoyles, the quadgun misses to wound my warlord. The bloodletters spread.
The 3 seekers left assault my termagants frontline and are wiped out with overwatch, so that the skullcrushers easy make their charge. The nurglings charge the gargoyles and make it, so do the screamers and the bloodthirster.
I loose many gargoyles (7 left) who only stay in contact with the nurglings (a few wounds) and the screamers (1 dead) ; it took me one quarter to explain the guy why his bloodthirster can’t keep stuck and shall stay in the open. A (big) handful of Tgants dies from the hellblades.
I lose the relic.
End of turn 1B:

The flyrants cross, the harpy goes ahead. The second wave (zoanthrope, tervigon, gaunts and dakkafexes) keep on moving. I spawn 12 gaunts.
I whiff with the psychic phase : almost all my powers are missed or denied (maybe paroxysm goes on the plaguebearers).
My warlord finishes off the horrors and herald unit, the other flyrant kills the disc herald, the harpy 4 daemonettes and the biovore scatter to the combat (killing 2 gargoyles, 2 screamers and one and a half nurglings base). The 25-termagant unit finishes off the chariot.
In assault the carnifex charges the skullcrushers and f*** all them off with the HoW attacks! The nurglings and the screamers wipe out the gargoyles.
End of turn 2A:

His reserves arrive : one horrors unit near the wrecked chariot; which call on the other horrors unit with the instrument. The flamers and the soulgrinder also arrive; leaving only the nurgle beast in reserve. Due to the icon from the 1st deepstriking horrors unit, the 2nd horrors and the soulgrinder don’t scatter (is that really allowed? I mean using the icon that was not on the table in the beginning of the turn). With luck, the flamers don’t scatter.
The bloodthirster jumps 1 ps away from the left dakkafex ; the screamers fly over the termagants in assault range of the biovores ; the plaguebearers and the bloodletters move ahead.
Warp storm does nothing.
The soulgrinder vomits on my termagants and kill around 7 and the flamers kill all the others but 2 (actually, shall not only the guys under the flamer template die?).
The bloodletters miss their charge against the Hgaunts, but their grand brother doesn’t against the carnifex and leaves him with 1 wound remaining, losing maybe 1. The daemonettes assault the dakkefex who dakkaes them with overwatch. The nurglings charge the termagants and the venomthrope kill all but 4 gaunts but lose 4 wounds. Damned nurglings, they are very better than our ripper swarms!
The screamers kill two biovores but suffer 2 wounds. Still 4…
End of turn 2B:

My warlord hit the ground behind the bloodletters. The other flyrant turns 90° and comes back, so does the harpy, but over the plaguebearers, killing a few with spore. Left zoanthrope moves near the bloodthirster for a surprise, so do the toxgaunts. Right zoanthrope approaches the soulgrinder with a western-themed music. Hgaunts goes after the bloodletters, last-turn-spawned Tgaunts after the nurglings. I spawn 7 gaunts (3-3-1).
Psychic phase : psychic scream is cast but the bloodthirster passes the Ld test. Dammit! Warp blast does a pen to the soulgrinder but I then roll 1, nothing significant…
The harpy kills many plaguebearers and the dakkafex finishes the job…wait, no, still 4! Dammit again! The warlord kills half of the bloodletters. The other flyrant only manages to kill 4 horrors.
Tgaunts and mother tervigon open fire on the flamers and kill 1 and 2 halves (yes, the 2 Tgants in the bottom do a wound!).
In assault the Hgaunts kill the bloodletters without rolling dices (my opponent take them off for saving time). The bloodthirster is assaulted by toxgaunts but kills the dakkafex before losing 1 wound. Termagants beyond the wall charge the nurglings for nothing and the nurglings kill the venomtrope and 4 gaunts. Bloody silly things. Biovores and screamers whiff.
End of turn 3A:

Nurgle beast arrives ans scatter away from battle.
Plaguebearers move toward the relic. 7-horror unit moves to the ruin, the 10-one to the middle of the field. The flamers jump near the unemployed Hgaunts. The soulgrinder moves toward the defiant zoanthrope.
Warp storm sees the harpy suffers 2-3 wounds from Slaanesh’s anger (?).
4 horrors come from the portal.
The soulgrinder fires at the zoanthrope who loses one wound. It alos vomits on, touching the termagants behind, killing 5. The flamers evaporates the rear Hgaunts.
In assault, the screamers kill the last biovore, the bloodthrister a big handful of toxgaunts and the soulgrinder evaporates the zoanthrope. The nurglings finally suffer more wounds than they do, and miss a instability test: there remains one and a half base.
End of turn 3B:

Time to think about the relic! There would be no 5th turn.
Warlord jumps near the new horrors. The other flyrant flies over the big squad of horrors, so does the harpy, killing several of them with spore. Hgaunts take the relic.
Psychic phase : psychic scream is denied… nothing else was very usefull.
Tervigon and termagants kill the flamers. Dakkafex kill the plaguebearers… warlord kills a few horrors in the ruin. Flyrant and harpy many from the other squad, leaving 3.
In assault the bloodthirster leaves 6 toxgaunts alive. They manage to do 4 wounds and my opponent rolls 1-1-2-2 for his 3+ armor. Good bye great daemon of Khorne! Nurglings kill gaunts.
End of turn 4A:

Screamers go after the tervigon, soulgrinder after the dakkafex and horrors after the relic-holding-hormagaunts.
Fire from the horrors is not denied and 6 hormagaunts die, leaving the relic on the ground. The soulgrinder deals one wound at the ‘fex.
Screamers charge the tervigon and lose one member without wounding the MC. Horrors assault my warlord and are brain-leeched to death! The soulgrinder misses its charge.
End of turn 4B:

my opponent concedes. VICTORY !

My deployment was bad… I should have deployed the Hgaunts first, keeping the gargoyles in the rear for counter attack. And the units were not spread enough.
The dices were good, actually quite balanced for me and unbalanced for my opponent (many good saves for PB, nurglings and horrors, good DtW rolls but failed book, bloodthirster last turn saves…).
I should have made a cordon around the biovores to prevent them to be assaulted.
I shall not forget to spawn gaunts!
I like what the harpy did, but I think the crone is better because ignoring cover saves and S8 VS.
BTW, MoA and 1st turn is good, specially against daemons with grimoire, summoning herald and other buffs.