Dealing with Aetaos'rau'kelas

I recently had a game against a Daemon list that caused me some real trouble.

The crux of the list was the titanic Tzeentch Daemon Aetaos'rau'kelas, who has similar stats to a Wraithknight, except his save is invulnerable, and has three extra wounds. He was supported by three other characters, including The Changeling, which meant there was a -1 to hit against Tzeentch Daemons.

The army deployment was just the big guy, along with 3 other characters hiding behind him, so I could only shoot at the big guy. They were able to come forward turn one, shoot and smite down a couple of units and be fairly close to in my face.

Turn one I did minimal damage to Aetaos'rau'kelas, and then turn two I had the remainder of the Daemon army summoned close to me. Ultimately I managed to down the big Daemon, but couldn't do enough to the rest of the army.

Without heavily customising my list, any suggestions of how to take that list on?

is the -1 to hit also in CC?

Flocks or kabalites screen to absorb smiles for sure. And stay as far away as possible to prevent charges. Once army is summoned I'd try to outrun them.

When I play tzeentch, Magnus time warped up and I rapid fires him down by turn 2. So if anyone splits of focus then down

The -1 to hit is also in melee provided The Changeling stays within 9" of Aetaos'rau'keres.

I did set up as deep as I practically could, but with a 20" move a turn two assault is pretty much guaranteed. Sitting back limited my ability to back up, which probably caused me more trouble than it helped. He can also shoot despite being in melee, so isn't at all limited by that.

Maybe try to tarpit big guy with wyches, and go hunt the characters with mobiles assault/heavy wepons (reavers with heat lances, or snipe with scourges).

We can reposition pretty well, and if his army isn't deployed turn 1, you can have access to his heroes a little more easily, maybe ?

Could be worth a try. He can shoot out of melee, but the Wyches would at least be a waste of his melee abilities, and wouldn't be much of a loss to his smites. My normal list doesn't have Wyches in it, so couldn't have thrown them at him.

What I possibly should have done in that game is use the Voidraven and Mandrakes to surround his army turn one, so that he didn't have any space to drop any summoned Daemons (I didn't realise summoning is a movement replacement).