Just a little fun theorising: the imperium is finally overthrown, the corpse emperor unplugged and the Galaxy under our control - so what else would we do than turning against each other.

Round 3 - Night Lords vs Alpha Legion

Who would win this confrontation. Please try to keep personal preferences out and reason your vote and please don't vote without saying why you voted that way.

Same situation as previously: the warp has just begun to consume the galaxy so it's pretty much the way it is now, just without loyalist scum.
All legions, or rather what's left of them, magically reunite after the imperium is gone to fight for supremacy.
For fights between legions, chapters or warbands which deviate too much in numbers we're just gonna leave numbers out and base on tactics, weaponry, ect. ...

Voting for Alpha Legion here. I admit i know very little about the Night Lords, so i'm a bit biased.

From what ive been able to read and research about AL, they would have the experience and information to play the same game as the NL but with a varried group.

We see AL as anything from renegade and not corrupted by the warp to AL sorcs and kornites full of the warp.

Honestly, I'd say we don't know enough about the two legions full capabilities to say for sure. The alpha legion is secretive AF and we don't even know if their primarch(s) are alive and their true allegiances, and the Night Lords are just not that focused on and given varying data, being mid sized to one of the biggest legions for example. If someone can dish out some extra info, that'd be great.

though it is skirting 'plausibility' the AL is known to field specialists in fields they know they'll need, as well as using any non-astartes for the jobs they need to do too. So if we count resources, the AL has a broader spectrum right?

Fear is a potent tool in any army's arsenal, but Resourcefulness and Adaptability are what can win wars more handily...in that regard Alpha Legion's got a steadier foothold IMO. For the Emperor!

Alright, so i was figuring i'd go to bat for the AL and wait for a NL aficionado to fill in their stuff.

Alpha legion openly uses anything that gets the job done, cultists on up, mutation or not.

Their exact numbers are unknown, but have had history of showing up with trained units for the tactic at hand.

Psychological techniques don't really seem to work on the Alphas, as they supposedly lost their primarch in a siege and didn't let up an ounce.

Apparently the Alpha Legion fielded 'banestrike' bolts during the horus heresy which were designed specifically to combat ceremite plated enemies.

EDIT: also one of the twin primarchs is still breathing, so fielding a primarch in battle too.

But, Alpha Legion relies on informants in many scenarios. If there's one thing Night Lords are good at, it's making damn sure humans don't do something they don't want. They could possibly shut down much of the informant networks through terror campaigns.

Sowing distrust in the ranks is basically useless. Nostraman society is built on distrust and murder more or less. That's excluding the multiple instances where Night Lord gene-seed has given limited premonitions into the future. Where other enemies stand by certain codes of honor, Night Lords play dirty. Alpha Legion would have to work extra hard just to draw them into a conflict that wasn't stacked in the Night Lords favor.

The counter attack against the Ultramarines is usually credited to the fact that they had an extra primarch to coordinate them after Alpharius "died". They are incredibly disciplined, but they're good at hiding in plain sight. That doesn't necessarily mean that they couldn't be affected psychologically, especially once information networks began shutting down. If they're in a deathmatch scenario in a solar system or small group of them, the Night Lords would simply target the most defenseless areas of civilians then broadcast the show everywhere else. People might not be so willing to be informants then. Also, they rely heavily on a decentralized chain of command. In the novels, each marine would have their objective, and they weren't supposed to deviate until new orders were received. Alpha Legion often tricked its own marines as a redundancy mechanic. Once enough gaps appear in that structure, their strength evaporates. Night Lords are essentially a bunch of warbands who share a generalized allegiance. Death from one thousand cuts instead of the coils of the hydra.

banestrike rounds are from HH anyway

Remember, Night Lords grew up on a planet where being stabbed in the back was simply a common reality.

this sounds like stalemates, false victories, and a scenario where no one on the outside could even tell who were the fighters or if any of it really happened.

do these rounds allow 'ties'?

Oh, you'd know where the Night Lords were. Jurassic Park: Lost World gave the best advice, "follow the screams".

The major issue is that even the reader gets Alpha Legion'ed in the fluff. You don't know what side their on or what their ultimate goal is. If it's an extended campaign, Alpha Legion will get what they need most likely, and that might not kill that many Night Lords. In a straight up fight, Night Lords would probably win.