Terror Assault is the Night Lords unique rite of war. It accentuates what the Night Lords can do but other legions cannot: cause fear, use night fighting as their friend, and fundamentally: take lots of terror squads. Indeed, with this rite of war, we are forced to take 3 entire terror squads.
The other thing that the Night Lords can do that others will find hard to accomplish is have their terminators deep strike in to play in any game - and not require a rite of war to do so.
The only question in my mind here is whether to take Sevatar, or whether to opt to take a generic Praetor instead for this rite of war. Sevatar is excellent at what he does, and does grant Master of Ambush but his big drawback is the 3+ armour save and the lack of eternal warrior. Plus, terror squads have infiltrate regardless. It is for these reasons that for the Terror Assault rite of war that I'm going to select a generic praetor instead.
Army List. (1850 points limit).
Praetor, terminator armour, teleport transponder, trophies of judgement, paragon blade, digital lasers, volkite charger (192 points).
This HQ gives us access to Master of the Legion and is kitted out for close combat. He is to be placed with the other terminators, below.
Master of Signal, artificer armour, Charnabal sabre, melta bombs, trophies of judgement, volkite charger, refractor field (135 points).
At first, selecting a legion Master of Signal over a chaplain might seem like an odd choice. But here, I'm using him for access to a Charnabal Sabre. So why a master of signal rather than taking a champion (and therefore a master crafted sabre?) - the answer is that he provides some much needed bombardment action for the army. After using this, he is a close combat monster with improved initiative to try to ensure that the lower striking members of any squad he is with can take advantage of their superior numbers inside combat. Place with any of the squads below you feel will most benefit from his BS bonus he can give to them.
Legion command squad, in terminator armour, thunder hammer for the sergeant, 2 chainfists, teleport transponders (210 points)
A fearless close combat squad designed to take out vehicles. Take a risk by deep striking them close to a valuable target. Team up with the praetor if needed. A bit of a suicide squad really. Could easily be replaced with a tactical squad instead. I include it here simply as an entertaining option (but pricey in terms of points). The choice is stark: 3 terminators to suicide strike a vehicle, or a large tactical blob. I can't quite make my mind up, so I'll leave the terminators here for now(!).
Terminator Squad, 10 members, 5 chainfists, teleport transponders (475 points).
Another teleporting squad. Can be teamed up with the praetor as well.
Mortis Dreadnought, two twin-linked lascannons, havoc launcher (170 points).
An anti-air option for pesky fliers.
Terror Squad, 5 members, Headsman with artificer armour, melta bombs, Nostraman Chainglaive (150 points).
A generic and small sized terror squad for causing fear in enemy troops and softening them up. To be infiltrated.
Terror Squad, 10 members, 9 with volkite chargers, 1 with a flamer, Headsman with artificer armour, melta bombs, power fist (285 points).
A kitted out terror squad, fit for infiltration.
Terror Squad, 9 members, Headsman with artificer armour, melta bombs, power fist (215 points).
Drop Pod (35 points).
A squad to team up with the Master of Signals if required, or to go it alone.
How it Works.
Arguably the big negative about Terror Assault is the lack of focus on support elements that can help with an anti-tank role. This is fundamentally why we have both the mortis dreadnought (which is arguably a HUGE target), as well as melta bombs absolutely everywhere.
The army relies on deep striking the terminators and drop pod, and infiltrating or outflanking the terror squads under the cover of darkness in the early turns to get in to position and take care of enemy tanks whilst ganging up on enemy infantry squads and trying to fear them off the table.
The sheer troops count here is an issue though. I would therefore contemplate getting rid of the command squad and having a tactical squad instead.
Expansions and Contractions.
More tactical marines for bodies on the ground is really required to make things shine here. Add in some transport options and I think we have the basis for an excellent army. Particularly if we can wrangle a land raider dedicated transport. Other ideas include having more dreadnoughts present as well. A Sicaran would be a sound choice too as would a destroyer squad. These are just ideas, clearly there are plenty of ways to expand up to 2000 points and beyond. I would also entertain heavy chain blades on some of the terror squad for fun. Gah, and I don't even have any lovely night raptors in here yet either. Heck, there's such a lot of choice for expansion.
To cut down to 1500 points, ditch the expensive command squad, and consider the necessity of the dreadnought if you know the opponent, otherwise its probably the master of signals that is going to face the chop.
The weakness this list will have is against fast moving enemies that are based on bikes (etc.). It could really benefit from some more ranged firepower, or fast elements of its own (night raptors, or storm eagle transports). Fundamentally, its a bit of an alpha-striking army list. Just pray that your opponent is not a fear immune legion (Salamanders, Death Guard) who are riding bikes everywhere (unlikely, but I'd love to see a Salamanders bike list!).
I will write at least one more Night Lords list, and in that one will try to focus a bit more on swift moving elements.