You deice to check with Yasha first and foremost. It may or may not work, doors may open or close, but she has been with you through everything, from the day she brought the Aegis out of the Kania Maw. Given your changed anatomy and her psychic abilities, any child you would make with her would have a high chance of having some sort of psychic abilities and / or physical deformities. And you are not even sure that her body is capable of producing 'natural' children anymore, not after Kamas turned the lower half of her torso into so much mush. Ariavari did a spectacular job healing her, but did that healing extend to her womb? Yasha didn't seem to think so the last time you talked about it with her, but perhaps Ariavari or Anai could help. If you can find them.

If Yasha is unwilling or unable to go that route, then it might be possible to create a heir via artificial means, using your and Yasha's genetic material as the parental blueprints. You don’t know of any Imperial facilities capable of doing so, nor of any Magos Biologis you can trust enough, but perhaps Mu'randa's Tau connections could prove useful. Their grasp of technology is better in some areas, to a frightening degree. But first you need to talk to Yasha. You knock on the door to her cabin, and enter.

"Yasha? How are you doing?"

Yasha looks up from the letter she is reading. "Fine Tristan. What brings you here unannounced?"

"Us, actually. Up for a little family planning?"

"You know that I can't bear any children."

"I know, I read the same medical reports you did. But Ariavari healed you once, perhaps she could do so again? or perhaps Anai could..."

Yasha cuts you off. "No, they couldn't. Trust me on this Tristan, they couldn't."

That not-human part of you whispers in your ear "She lies..."

You take a seat across from her and make sure the hatch is closed. "Walk me through it then Yasha. Why couldn't they? Ariavari's biomancy put you back together after you had gone septic multiple times, had at least two total blood replacements that I know about, put your intestines back together from so many scraps of severed flesh, and make it all work again. Plus you came out of that with some impressive flexibility. That thing you can do with your tongue when we..."

Yasha coughs, a crimson blush spreading across her face. "Yes, well, uhm."

You just wait while she regains her composure.

"From a technical standpoint, I suppose it is theoretically possible that Ariavari could restore organ function again. The complication would be that she would have to saturate the organ with warp energy. That can twist the form of an adult," she makes one of her inhumanly-fluid gestures indicating the both of you, "the effects is would have on an unborn are too chaotic to predict. A child conceived under such conditions would almost certainly be psychic, probably a navigator. Equally certainly, that same child would be physically deformed. It might be as insignificant as what I was born with," she waggles her overly long fingers, "but probably not."

"We've beaten long odds before. what makes this any different?"

"These aren't just 'long odds'. The only child that would survive without physical deformities or psychic powers would be a blank, a living anti-psychic dead zone. And carrying such a child to term would likely kill me.

"Ok, that conclusively rules out Ariavari. But what about Anai? She did give up these." You tap the brass scarab 'tattoo' at the base of your throat. "She could probably give us a purely technological solution."

"The same reasons that I turned down that gift would likely apply to any help she could offer. And look at the cost last time she was involved. Your leg and eye, my womb, Adam's life, Elena's sanity, Rubicon's arm... Even if we could find her, and even if she had a workable solution, the cost would be at least as much again. No, better to leave them well enough alone."

"Alright, that leaves the in vitro option. I don't think we could find a trustworthy source inside the Imperium, but we do have indirect access to Tau medical technology."

"That may work, assuming the Inquisition doesn't protest. But wouldn't taking a concubine or two work better? Assuming you can find one who isn't a psyker, and who is willing to, ahem, with you and perhaps..."

Fellowship Test Successful: Critical Success. Pancakes Ensue.

Several Hours Later...

You are awoken from your post-pancakes nap by an urgent message tone on your personal communicator. Grumbling, you silence the device and pad out of Yasha's bedroom before accepting audio only. "Tristan here. Go ahead."

"Jace here sir. A Mechanicus Explorator and / or salvage ship has arrived in system. Its commander has identified himself as Magos Explorator Alieus Rex."

"Ah, shit. I'll meet you on the bridge in fifteen minutes." You close the connection and start looking for your pants.