This story is a sequel to Friendship For Gearheads

Barron Secht, Archmagos Dominus, has done things which less flexible Imperial factions would call Heretical. He has adapted designs from Xeno tech-heresy, offered to negotiate with the unclean, and he's even gone so far as to cancel an Exterminatus--on the grounds that the very Machine Spirits themselves willed the ship's thrusters to quietly die.

He has spent the past two weeks attempting to understand a new kind of xeno--a race of quadrupedal sapients who have no knowledge of the Warp, or of War--but they have shown a capacity for learning and understanding beyond what the Imperium has ever reckoned with. The one called Twilight Sparkle recreated a lasgun design long thought lost. What other knowledge do they hold? Secht cannot afford to lose such valuable tech-lore.

Suffice to say, when he learned about the chaos god living on the edge of Ponyville, he was not thrilled.

Contains my best guesses at what Warhammer 40K canon is. Special thanks to Opponent, who wrote the comment that inspired this sequel, and who graciously loaned me his OC to play with. Also, shoutout to the WH40K wiki, and my buddy Tupo over in Estee's discord server, because dear Emperor this game's lore is dense.