[@Jbcool] In all fairness, you being the game master. You are the warp.

But i agree to an extent. While not a mary sue, it is in the danger zone. However, the ritual performed is one that has been performed multiple times before, making him used to the problems with it.
Also, the two powerful deamons work against each other so that the other doesn't get the ork in the end.

On one end it's kinda mary sue. On the other it is grounded in lore.
I will stand rather neutral on the subject matter.

But warp thingies starting to happen i'm all for. I could roll up something from the dark heresy psychic phenomena table if you'd like :D
(I'm gonna do it anyway, so people get an idea, and the gm might want to use it.)

[hider=Examples]
Three rolls on a d100 table.
11 = Mounting Paranoia: The Psyker gets an itch between his shoulder blades for a few moments.

46 = Bloody Tears: Blood weeps from stone and wood within 3d10 metres of the Psyker. If there are any pictures
of people or statues in this radius, they appear to be crying blood.

88 = Roll on the Perils of the warp table >:D
(Let's "roll" the same as one before to givr an example of how evil the perils table is.)
46 = Psychic Mirror: The Psyker’s power is turned upon him. Resolve the power’s effects as normal but the power
targets the Psyker instead. Should the power be of benefit, it instead deals 1d10+5 Energy Damage to the Psyker
and the beneficial effect is cancelled. Armour offers the Psyker no protection against this Damage.

1D10+5 energy damage is roughly equivalent of a high power lasgun blast.
[/hider]