Here's my analysis on some of the more potentially dangerous options.
Establish new Recruiting Worlds for the Blood Angels
Making Dante the Lord Descendant of Nihilus is already putting an unprecedented amount of power in Astartes hands. Like it or not, the High Lords are, to what some would consider an irrational degree, fearful of the Angels of Death, who once betrayed the Imperium in the heresy. It is no secret that much of Pandora's political support in fact, comes from the ranks of such posthumans, as well as others that might be tarred with a similar brush.
If we were to increase Dante's ability to recruit, it should be through a founding of new chapters. Atleast that has the veneer of not being legion-building.
And besides, it's been an accepted norm that the First Founding Chapters maintain the ability to call upon their successors.
[] Help establish a local branch of the Telepathica here to train new Psykers and Astropaths now that travel to Terra is even more harrowing than it normally is. (1 Year)
Many of the Primaris Psykers joining the Expedition are here for this reason, but your personal involvement will help establish a firmer foundation. You're probably their best hope for an equivalent to the Sanctioning process anyhow.
Our influence over the Adeptus Astra Telepathica is already clear, and such actions will likely go without complaint on their part... but not on the part of the Inquisition, especially the Hereticus,
nor perhaps even the Sisters of Silence and even the Custodes. If we are to create such a method, maintaining the Black Ships and the Tithe they bear, as morally damning as they are, would be serve to maintain the loyalty of the Talons and show that were are yet regent of the Emperor.
And of course, there are those amongst the High Lords who would see any diminishing of Terra and Segmentum Solar's absolute pre-eminence and the independance of another segmentum as a threat to their power, no matter what.
[] Teach the Wayfarer Discipline to the Navigators of the Baal Sector (1 Year)
Without your help or the Astronomican, Warp Travel past the Great Rift will be both slow and dangerous. You may as well see if you can't teach Navigators to see the same way you do, since every bit helps.
[] Teach the Wayfarer Discipline to the Primaris Psykers establishing the Telepathica Branch (1 Year)
The Navigators will always be outnumbered by natural born Psykers, and they are both more vulnerable and more valuable targets here anyways. Teaching the Telepathica the Eyes of Pandora - or the Wayfarer Discipline, that seems like a better name honestly - will ensure that the practice is less likely to die out.
[] Teach the Wayfarer Discipline to the Librarians of the Blood Angels (1 Year)
For all you claim that Chaos does not corrupt as much as people think, subversion is still a very real risk. The only people you can really trust not to fall to Chaos, even accidentally, are the Space Marines, and they will need the speed more than the rest. Anyone remaining on this side of the Rift will need to learn your methods.
[] Teach the Wayfarer Discipline to all Psykers willing to learn it (2 Years)
If you're going to be teaching someone, you may as well teach everyone. Travel is slow and Chaos is everywhere, so it will be better to equip everyone who needs it with the tools to get around and level the playing field.
The Navis Nobilite will throw a fit no matter which of these we pick, even if one of them is more or less inevitable.
Yes, even if we pick Navigators. The Navigator houses are constantly jockeying for power and giving one group of them such an advantage, even temporarily, or even interceding in their affairs like this is still a threat, and the idea that you could teach others, even more of one. We will have to alienate them and spend political capital here, and we must keep that in mind.
[] Offer Dante a contract with your Deva to guide ships through the Warp (1 Year)
Ships in the service of Chaos tend to be unusually fast and precise in the Warp because Daemons are leading them through its tides. Your Deva can do something similar - a bit better actually, since the power you imbued in them also helps them navigate the Warp better. Speed is key to unity in the Dark Imperium, so Dante will want every edge he can get, even though this is pretty much heresy to anyone looking in from the outside.
This too. It will still alienate the Navigator Houses and some sects of the Ecclesiarchy. It will alienate some and attract other members of the Inquisition. Your Divinity is always going to be a tool and a threat. I say this not as a damnation of these options but merely as a statement of fact.
We are going to make enemies here.
[] Reveal your divinity to the Blood Angels (Free)
Sanguinius has a point and is even willing to bat for you here. Dante is a peer and a kindred spirit, so it's only fair that you come clean if you want him to do your bidding. Reveal your divine nature to the Blood Angels, so they can help you keep people alive. Must be taken before any other actions in this category can be done
I
personally believe this is the wisest course of action. Although I feel the need to warn people that the Inquisition is implied to maybe know of the Red Thirst and simply tolerate it... do not expect Pandora's divinity to remain secret forever.
[] Manage the future Cults of Sacrifice (1 Year)
You have made something of an impact during the fighting, and you doubt that everyone is going to attribute every last bit of it to your father. While flattering, it does present a risk to them since technically worshipping you is heresy, and the nature of your cults tend to make them very public targets to get shot at. Your Deva won't be able to manage them, so you will need local authorities who can. And the only local authorities you trust are the Blood Angels.
If only we had a friendly ecclesiarch to spin these...
Ah well.
[] Offer to induct the Blood Angels as your Chosen (1 Year)
Every Chaos God has claimed a Space Marine Legion as their own. Khorne has the World Eaters, Nurgle has the Death Guard, Tzeentch has the Thousand Sons and Slaanesh has the Emperor's Children. You could do something similar with the Blood Angels, who are already really close to you whether they realise it or not. This would empower them, maybe even help them manage their Curses… But it is very definitely heresy, and if anyone finds out they will pay for it dearly. But out here in the Dark Imperium, they may need every edge they can get.
Big risks, big rewards.
Also they might gain Devalike wings and that would be hillarious, especially once Sanguinius reacts to it.
Now, as for my personal reactions.
Well, that's about as much as you're getting out of him today. With some time you could probably work him over some more, but there's ten thousand things for you to do and you have time for maybe five of those. "Anyways, did you know that we have Blood Ravens?"
[]Doublecheck every inventory in the Sector to see what they were gifted.
-[]Check with Lily that you don't blame them for being gifted something she acquired.
--[]Send lily to Liase with them and totally not go on a looting spree.
