Did some thinking and added a bit more thought to my plans, if people like em, cool if other plans are more their speed, that's also fine. I just like to help spin the wheels of creativity.
[] Plan Ravens of Rhodes
- [ ] The Raven Guard: The Gene-Seed belonging to the Sons of Corvus Corax no longer has a Mucranoid or Betcher's Gland, resulting in the lack of the acidic spit and the loss of the ability to generate an outer coating to protect the body against extreme environments such as the void of space, and causes a cosmetic mutation in the form of unnaturally pale skin... but the Raven Guard, despite their crippled numbers after Istvaan III, are a worthy lineage as any other. They are specialists in stealth warfare, and are more capable in guerilla war than any other.
-[ ] Rhodes 77: A planet in the Ultramar region, Rhodes is an important hub world due to it's location along several of the most stable warp routes known to Ultramar. This makes the regions near the world a den of piracy both of the human and xenos variety. (Ultramar Region).
Upon reflection, my prior plan for the Ravens was not...stable. But this one places them on a major world for a region and while there are a load of pirates, consider who might try to sell weapons to brewing conflicts in local worlds/might aid them for a right price. And like the Raven Guard as a whole are good at dealing with insurrections, we've seen it before.
[] Plan Blue Bulls
-[ ] The Ultramarines: The most pure and stable Space Marine Gene-seed, the Ultramarines, sons of Roboute Guiliman, are a lineage that gives no great benefits but in turn does not have great downsides. They are tactically balanced, seeking to practice all forms of warfare rather than master just a few, and stand as the most numerous of the surviving Space Marines. They do seem to have started a minor tradition of maintaining ties with their successor Chapters, however. Whether this is a boon or a curse remains to be seen.
- [ ] Creetaz: A planet near Ultramar with a large number of the Abhumans known as Beastmen, whom have lived in shocking harmony with the human population. Normally Beastmen either fall to Chaos or end up in a mutually hostile relationship with baseline humans, but this world seems to have avoided both fates. Additionally, a stable sub-species of Beastman known as Minotaurs have been confirmed as native to the planet, and according to your records, are as large and powerful as Ogryns. (Ultramar Region).
Now this does look like a pretty normal chapter idea, but consider this for a moment, firstly the Ultramarines for all the Memes are Generalists and would probably be alright in what is needed for fighting rebellions. Secondly, those Minotaur's sound perfect for an Aux force to aid the Chapter, plus any other Beastmen sorts that exist on the world. And finally with some final tweaks in part two of creation, i can see something like the Deepstrikes or Extra Thunderhawks deliver large numbers of their forces quickly and where they are needed.
[] Plan Croc Hunters
-[ ] The Alpha Legion: The Gene-Seed derived from the traitorous Alpharius is, despite it's origins, very pure as the physical is concerned, with no noticeable mutations beyond the fact that Alpha Legionaires tend to so closely resemble their father as to be able to impersonate him convincingly. On the mental side the Alpha Legion's Gene-Seed seems to create more secretive Astartes with a greater sense of initiative, resulting in them being masters of intelligence gathering, sabotage, and all other forms of indirect warfare.
-[ ] MizzurI: A swamp planet, populated by an extensive variety of crocodilian xenos species. The locals have taken to wrestling with them, and are expert marksmen… though they do have rather strange accents.
Thinking on it more, this plan here has some potential, aside from the sneaky Alpha Legion stuff, they would have some martial merit from the world and would not be adverse to fighting directly. And like memes aside, i do believe that this combo would create one of the better Chapters to find out about rebellions and dealing with them quickly.
[] Plan War Riders
-[ ] The White Scars: The Sons of Jaghatai Khan bear no overt physical defects, yet the White Scars Gene-Seed has been known to make those implanted with it more savage and hungry for war. In honour of their Primarch's history as a master of cavalry, they have mastered the use of both Combat Bikes and the rarer Jetbike units, and specialise in high speed, hit and run battles.
-[ ] Fleet Based: The Chapter is fleet based and will be constantly on the move, but as a result will lack a proper home unless it decides to claim a world for its own in the future.
While the Sons of the Khan are more intrested in going out beyond Imperial space, making a group that is constantly on the move inside the Imperium's borders makes some sort of sense, and I mean they would be more used to dealing with things quickly. The chapter base of White Scars might be a bit too specialized for this kind of work, but if we wanted the option which would deal with things quickly, this one exists.