The unnamed conjurer claps his hands and orders two of the fiends into battle by pronouncing their True Names.

Axi'manithazimungus, Goganikranjimugi! Kill that wizard!

He then casts a spell that you know to be Lower Resistance (only he's Quickened it).

The winged fiend lifts its clawed hand and points one long talon at the lich. A series of balls of fire streak out from that hand.

The third Fiend lumbers forward, having begun to move the instant you cast a spell.

Spoiler
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Let's assume we're the standard 200 ft distant.

One of the fiends was operating under the command Defend Me, which is one of the examples given in the class feature description.

The two Hellfire Engines move towards you rather slowly (a rate of 40 ft).

The Paeliryon uses Meteor Swarm as a spell-like ability, Empowered.

Ranged Touch 1 - (1d20+31)[44]
Ranged Touch 2 - (1d20+31)[32]
Ranged Touch 3 - (1d20+31)[47]
Ranged Touch 4 - (1d20+31)[43]

Bludgeoning 1 - (3d6)[13]
Fire 1 - (9d6)[27]

Bludgeoning 1 - (3d6)[17]
Fire 1 - (9d6)[41]

Bludgeoning 1 - (3d6)[12]
Fire 1 - (9d6)[28]

Bludgeoning 1 - (3d6)[10]
Fire 1 - (9d6)[28]