Here are some snippets from Magnus and the imperial cultists adventures in the warp. Janus replaces drago.
Magnus: You guys are the first non hostile sentient creatures I have encountered.
Decius: What about Janus?
(Magnus chuckles)
Magnus: the definition of Sentience is the capacity to be aware of feelings and sensations. Now considering that, does Janus really qualify?
Janus comes from offscreen: NO!
Decius: I agree with Janus.
Magnus: Ok, i'm gonna head off with captain crazypants over there
Janus starts singing i'm the model of a modern major general in the background
At a Nurglite village
Magnus: How do you want to go about wrecking this place?
Janus: We shall chuck Vortex Grenades at them!
Magnus: But Vortex Grenades send a target to the Warp. And we are in the Warp.
(excited nerd noises)
Magnus: OK, in the name of scientific discovery, we shall initiate this experiment. Do you have a slingshot on you?
(decius shows up and alerts the Daemons)
Magnus (annoyed): Janus, go handle them whilst I deal with the priest
Janus (to theme of power rangers operation overdrive): Go Janus, Go Janus, go, go, go
Janus blasts off
Magnus approaches Decius angrily
Magnus: Alright you chair bound idiot, you had better explain yourself now! And know that i left what little patience i have for fools, especially of the delusional nature, in the BURNING WRECKAGE OF THE FENRIS SYSTEM!
(Decius explains what happened as he knows it, think Kazamovs speech in tts 24)
Decius: A monster lurked there, an evershifting horror marked by twin angel wings.
Magnus (horrorfied): An evershifting horror marked by twin angel wings. Sanguinius is on the Throne World?!