- The Nightbringer reminding how terrifying he can be
"When the Grim Reaper comes to call, words fail- they're just too small."
- - Dixie Lyle, To Die Fur
"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it."
- - Terry Pratchett, Reaper Man
Aza'Gorod AKA The Nightbringer, Warhammer's Grim Reaper, Necron's Mortarion, FUCKING CHEESE! is one of the main C'tan gods in Warhammer 40k alongside the Deceiver and the Void Dragon, that is still relevant enough to be talked about. The other C'tan gods are either eaten, shelved in a GeeDubs corner or have little to no limelight. The Nightbringer is known as the entity that single handedly enforced the concept of the fear of death or at least the Grim Reaper in the 40k Galaxy.
He along with the Outsider, another C'tan was infamous for being a team killing fucktard during the War in Heaven after he and the Outsider were tricked by both the Deceiver and Cegorach to eat his fellow C'tan brethren in order to gain more power. As you can imagine, things did not go too well with the Necrons and the C'tan during that incident. Making the Deceiver one of the biggest walking fuck ups in 40k history.
Consequently, the Nightbringer alongside the rest of the C'tan save for maybe the Void Dragon and the Outsider was stabbed in the back by the former slaves; the Necrons and subsequently turned into fucking Pokemon after being blasted into a million pieces. You can say all you want but at least Khaine was treated with dignity and respect by the Eldar after he was shattered by a bajillion pieces unlike the poor C'tan who have turned from one of Warhammer's most sinister forces into a fucking joke.
On the Tabletop
Before the Warddex, the Nightbringer was the hardest thing to kill outside of Apocalypse with toughness 8, five wounds, and a 4+ invuln save (Remember when that was impressive?). As a monstrous creature with S10 and loads of attacks that ignored invul saves, getting near him was a death sentence. The Warddex removed it entirely in favour of more customisable C'tan Shards. It was re-introduced in 7th edition, in a weaker state, in an edition with rampant power creep and in a codex with the strongest Necron roster yet. The C'tan went from being one of the most cheesy units Necrons had, to one of the weakest. Noticably a Relic in the Shield of Baal makes the Nightbringer Toughness 8 instead of 7, making it no longer die to boltguns, which is sort of a big deal if your opponent isn't playing Dark Eldar.
8th Edition is the return of the Nightbringer. While still at toughness 7 with 4+ save and 8 wounds, he is now a character and thus unable to be shot at if he is not the closest unit. This adds so much to his survivability and he can now actually make it to close combat. However, the biggest change is that now the Nightbringer can Rip and Tear virtually anything. His weapons are Gaze of Death (Assault D6, 12" range, -4 AP D3 damage) and Scythe of the Nightbringer (AP -4, D6 damage). Both of these weapons hit on 2+, thanks to the Nightbringer's Ballistic/Weapon Skill, and wound on 2+ thanks to their own special rules. On top of that, he gains 1 Power of the C'tan. The most useful one being Antimatter Meteor, which is basically a 24" range Smite. Time's Arrow can also be useful in certain situations where you want to snipe out an annoying character. Seismic Assault seems the weakest of the three powers, so it is not recommended to ever take it.
Antimatter Meteor deal D3 mortal wounds, so an average of 1.5 is expected. (Yeah cause the average of 1, 2, and 3 is 1.5.) Seismic Assault deals a mortal wound on a roll of 6 and rolls one die per model in the closest unit. To reach the 1.5 average of Antimatter Meteor, you need to roll 9 dice.
Of course, 1.5 wounds do not exist so you either get 1 or 2, so dice rolled for Seismic Assault are adjusted appropriately to 6 or 12. However, while Antimatter Meteor loses when there are 18+ models in the unit affected by Seismic Assault (which is already a lot of models for a unit to have), it gains an extreme edge when targeting small units and can seriously damage single-model units, such as characters, which are basically unaffected by Seismic Assault. A small thing that Seismic Assault gains over Antimatter Meteor is that it goes off automatically while Antimatter Meteor goes off on a 2+. You still get it 5 out of 6 times though...
Bottom line, if you play Necrons you always take the Nightbringer. No questions asked, he is too good not to take and he even costs just 230 points (or 12 power, if you play Power Levels), which is nothing for what he offers in offensive power.
DoW Dark Crusade
The Nightbringer also appeared in Dawn Of War: Dark Crusade, sorta. The Necron Lord has the ability to turn into a manifestation of the Nightbringer, which skyrocketed his DPS (not as much as what Relic units had, but still high - enough so that when executed properly and against careless players to don't move their units out of range of his scythe, the Nightbringer will flat out kill any of the other race's Demon/Relic units before his timer runs out), but more importantly, he was INVINCIBLE while the ability was active, meaning the best an opponent could do was to hold it in place with a bunch of infantry until it wore off and hope it didn't kill anything too valuable.