So, you want to be a sneaki boi? Good for you.
For basic info refer to ES2 wiki[wiki.endless-space.com] - lol nvm, they did not even post hissho yet, kek!
Open your game, browse the traits, don't make me produce copy pasta content, you are not that stupid.

• Sneaky, invisible by default
  
• Single system, single management, easy life, strong % stacking from mods and wonders and per planet bonuses of sanctuaries
  
• Fleet spawning across sanctuaries, kinda like portals but sneaky!
  
• System sharing + extra hacking bonuses...
  
• Super fast early expansion, if RNGod provides

• Manpower issues which can be dealt with with bandwith usage, but not much, you will preferably need to outsource MP somehow to switch troop profile.
  
• Fixed bonuses and most NOT cold/sterile pop bonuses from upgrades rendered much less relevant, but you can skip those then!
  
• Can get blocked off from/heavily slowed down on further expansion kinda like unfallen with vines, but more adaptible. See video at the end.
  
• Can get boring quickly, as there will be turns with literally nothing to do - hacking ops are up, your home production is up, everything is arranged, other players still have minutes left on the timer. A backup game to switch to comes in handy. I go trough dailies/farm something in other games throughout the MPs.

Just try to hack all the time, only don't hack if there will be something better to hack next turn and you want to save slots. Otherwise follow the lyrics of Butcher Pete song from fallout.

For more info on hacking, you should probably refer to the "Hacking guide" I made. That would be very smart!

So you hack free nodes to create free sanctuaries and then carry on doing that until you reach conquest victory... but WAIT WHAT? There are enemies in the way?

That's cool, you can either obliterate them through your sneaky magics or start hacking their systems.
When you have 2 sleepers placed on an enemy system, you can then start putting sanctuaries on it = owning said system ASWELL as the other player. You can win supremacy without invading a single time.
Hacking home yields even better results and is encouraged, although difficult and should be attempted through proxy hacking, as the guide suggests.

Yeah, I have made yet another guide for that, because again, it's not faction specific!
Would be very stupid to just post it in an UC guide right?

Since you can not have minor pops and you only have umbral shadows as your superpop, you should not be able to boost pop growth, but... you can! But it works differently, it works better!

Boosting increases your population gain by +1 science and +1 BW, this on UC means it DOUBLES your pop bonus per pop. This also applies to umbral shadows.
This is espcially important because of the BandWidth, you can sometimes run out of it through your hacking and beaconing attempts, and this provides a welcome addition.
You should boost if you can afford it and if you need the BW.

Umbral shadows are your empire superpop.
This is well explained in game tutorial. but I will elaborate.

You can obtain umbral shadows through following means:
Abducting sleepers.

Yup that's it, let's see how we can abduct sleepers:

• We hack a system with a sleeper on it. Or home system of the faction which has the system we have sleeper on. - this is slow and tedious as you can only abduct one from a system and two from home, but "easily" achieved
  
• We succesfully invade a system with a sleeper on it and select an ABDUCT action. You need a fleet fort this, but you can get 40 shadows at a time.

More on obtaining said sleepers on systems in the first place in the hacking section.

Shadows, the "superpop" acts like a better counterpart to our basic pop, it fills up your home system replacing the old UC pop, until its full, then sleeper->shadow conversion results in science and dust gain, which can be further increased by researching the influence system conversion tech, which is altered for this purpose, as you can not convert via influence.

Shadows serve as a FIDSI multiplier combined with your starting hero skill resulting in a strong home system boost, once filled to max. As presented in a picture:

Basically past leveling on curiosities place your starter on home and keep until end.
Becuase of all the centralized production and output your hero will be one of the fastest leveling ones in the game.
You can speed this by pushing out more ships. For queue filler consruct a scout with single +10 science/percloacked fleet/turn (quest reward).
But you have to create fleets of one out of them, else it does not work and that's annoying.
UC heroes also come with max detection skill on T3 skills, which can come in not only handy in mirror matchups.

Leveling:
Do not add skills until you are promted by quest to raise your BW to X, then spend your skills on +10 BW for almost instant compleition! You are welcome.

Since UC also have only one system, adding +20 approval on your hero is extremely viable in the early game if you are expanding enough, same goes for bonus influence
While bonus industry is relatively weak compared to the guardian bonus, it is outweighted by the counselor ultimate, which while not setting ecstatic, eliminates most of the problems with approval.
Finally the shadow bonus becomes relevant once you have any, and on maxed system of 45 translates to +45% FIDSI which combined with eco behemoths results in very strong system.
Otherwise feel free to spend wherever you need!

AFAIK the main quest forks at the point where you select hero reward vs hero tech reward.
Hero questline is more combat friendly ending with +30% fleet evasion bonus, while the hero tech questline is more hacking friendly getting you bonus BW/ or hacking speed per backdoor law and finally ending with +1 max hacking operation

I believe I have outdone myself preparing a simple lazy almost-flow diagram of the faction's questline:

Ok, we have gone through almost everything faction specific there is.
Next is our big game masterplan!
Do we want to win? (This is a serious question given sometimes fapping over noobs is no longer entertaining, and since this is like day 3 of DLC everyone out of beta is a noob)
How?

• Easiest way is to conquest, since you can ignore other people owning systems once you get to it, and don't lose that many yourself, you are a prime candidate for a conquest victory! So just keep hacking and ... tada you won...
  
• Supremacy is also an option, if home systems are reachable and will get hacked/invaded/infiltrated by you prior to triggering conquest, you will win by supremacy, gz!
  
• Wonder is kinda meh, you actually can build multiple wonders at your home system, and with combined strength of all your sanctuaries, behemoth mods and high tier upgrades, you can pretty much dish out one wonder every 2 turns given you have the resources. But you will win with conquest sooner. But it IS an option
  
• Economy/Science is not impossible, but less of our primary focus, sophons still do it kinda better. But with full umbral shadow home + hero power for +1% FIDSI shadow on home, we are a superpower! But also at that time sophons already won. So probably no. Unless you can steal the techs from them! ;)

Early turns:

• Dont forget to lawyer up! Both party laws are viable straight form the start, if you are feeling lucky!
  
• Hack to expand. Prioritize pretty systems first cause pirate spawns.
  
• Hack nodes cause FIDSI and backup.
  
• scout and scan, with 4 probes on 2 scouts you are almost a guaranteed winner of "scan 10 anoms first contest". Congratulations on your balanced faction choice! Carry on.
  
• Upgrade home early, with some more scaling-friendly luxury, or use whatever you have, just try to maintain cloack level on home ahead of the curve. (home cloack level = system level till level 3, then it stay there)

First encounters:

• Pirates I recommend leaving alone, they won't annoy you till lategame while annoying everyone else.
  
• Don't worry, they can't see you, or shouldn't.
  
• Hack home for techs and to create messes! Hack through proxy.
  
• Either prep to engage or place sleepers and sanctuaries, or both! Cause it's not really exclusive.

midgame to endgame pewpew

• Enjoy your cloack and ambush while it lasts
  
• Don't forget to hack
  
• Utilize jam communications action on system hacks, it affects all player's systems resulting in "easier" invasion, which however can take longer as specified in the hacking guide.
  
• Utilize also other actions, be annoying, it's pratically free as long as you don't get caught.
  
• Keep expanding, you are number one runner for conquest win

Consult video section for more detailed approach on turn to turn basis.

Bear in mind that the two videos were recorded with me believeing the wording on Encrypt defensive program, which says it slows enemy hacking by 50%, this does NOT apply to traces. So, you will still probably place defensive programs around your border systems BUT for less effect than originally intended.

Here I post a fancy video from day-post-release game facing of mostly against the guy, who I believe posted the other UC guide playing as hissho.
Video presents all aspects of an MP gameplay, including desyncs, disconnects, server errors, long waiting times for other players which are filled with farming wow in the background. Also the game is not finished, cause we just gave up at a point when fleets stopped moving.

I played another, bigger, laggier, game to show you can be pretty aggresive in the early game, given the RNG provides. But if there is a 3rd party watching you beat each other up, you are inviting trouble. =D Ends at turn 45, as everyone bails after playing last 5 turns for 30 minutes over reloading, rehosting and resynching with end turn stuck.

Now a little smaller game of 3 players padded with AI, somewhat passive but at least we finished.

It's not like you have NO manpower, it's more like "oh I need X manpower to change the profile to full tank and later full air". But I have 0, cause my excessive unlimited expansion scores numbers of systems with not enough MP to fill them.
Let's list some less common sources of MP one might forget about, we have:

• Diplomacy - ask for MP, give something in return, if there is AI in the game, this should be easily attainable, as most of them have excess amounts?
  
• Scrapping ships - as in NOT selling them to marketplace, but scrapping them.
  Hold off on the selling tech, so you can scrap ships, scrapping ships returns some dust but it returns all the manpower! Notice that scrapping pirate ships, minor faction ships, random reward ships results grants you manpower for free, and you can even hold on to that MP for later purposes.
  
• Minor faction action - either getting ships and scrapping them (keeping them for scrapping later) or using the somewhat less effective action for +100MP works. First is kinda stronger, but eats the pop so is limited, second is unlimited as long as you have resources.

Well let's face it, UC are incredibly strong and when in a match of multiple players can usually rely on being left alone (and invisible) for 99% of the game and expanding unimpeded.

This will land you at a conquest victory real quick you just keep expanding and no one can stop you or even see you, only issue is the newly implemented heavy overexpansion drawback which you either counter through leveling hero and getting all approval stuff, or getting federation as usual.

Count systems and combine minor factions for big swings in system count in a single turn to close out games.

UC home is a prime contender for all competitive wonders - provided you have planets available, you will be one of the top producers.