Still looking for a way off the Mortis Thule, we are heading towards the Eye of the Inquisition that Brother Lucius recognised on an internal scan of the hulk. As we work our way up the corridor, we feel we're being followed.
Rather than directly confront our stalker, we drop a couple of hopper mines and dip in to cover. Unfortunately, what we notice is not an explosion but a humanoid figure neatly avoiding the mines. But at least we see her clearly now.
'Who are you?'
'I am Death Cult Assassin Claw.'
'...could you be any more of a goth?'
'Clorr, not Claw.'
'Even so.' But Clorr is looking for Interrogator Thirl, apparently a rogue member of the Inquisition, who has escaped capture and sought refuge in the Mortis Thule, the unlikeliest of places. It seems we are heading in the same direction, and bringing a traitor to justice is a good use of Deathwatch marines.
Onwards, to where a disturbing and highly unusual ship sits inside the Mortis Thule. Despite trying to make sense of its shape and volume, there is a distinct geometry that doesn't look to work. It's rather unsettling.
Moving in to the ship doesn't get much better for our states of mind, but we are able to cope with the weirdness. Stepping in to one section of corridor, however, has it vibrating, and we get a sensation of moving upwards quickly.
When the corridor stops vibrating we are clearly in the same ship but a different section, as evidenced by the hordes of mutants around us, all bowed in reverence. In the middle of the room is a shaft of black light...
'Black light? I think that's called "shadow".'
...inside which is a man.
'How can you see something lit by "black light"?'
'Use your imagination.'
'I'm trying! It isn't easy.'
The man is Interrogator Thirl, and the hordes surrounding him rise and turn towards us. But hordes are easy when you have psychic fire and fully automatic bolter guns. Waves of mutants surge forwards, waves of mutants are cut down or horribly charred, until it is just us and Thirl left.
Interrogator Thirl has been using his own psychic powers. One beam of energy missed Brother Lucien, one struck Clorr. Now that his mutant hordes have been destroyed, he brings out of the big guns. He summons his psychic powers and, well, that's not all he summons.
The psychic power Thirl tried to instantiate fizzles. But the energy goes somewhere. A connection to the warp is made, it is intensified, and Thirl accidentally summons a Daemon Lord of Slaanesh. The Daemon Lord focusses on Thirl, its summoner, and will remain until either it or Thirl is destroyed.
'Well, that's convenient. Have we won?'