How to roleplay a Death Knight

How to Roleplay a Death Knight
So, you want to RP the warriors of death that instill fear into the living? There are a few things you should consider.

1.Which Generation of Death Knight are you? (There are commonly 3 but a fourth is possible.)

2.Is it possible and likely that your race would become a Death Knight during that generation?

3.Why would your Death Knight wander in society?

The Generations of Death Knights
Death Knights come in different varieties. The first generation being the death knights of Gul'dan who were made from Orc souls infused in Stormwindian knights bodies. The second generation being the Death Knights corrupted by the Scourge during Arthas' rampage before he became the lich king. And the third generation is the Death Knights of Acherus, hinted in the game to be former Argent Dawn Members, but your backstory can be whatever you want, as long as it works. The possible fourth generation that was mentioned, was discovered during Eastern Plaguelands when Gidwin Goldbraids was kidnapped and almost turned into a death knight by some higher ranking remaining scourge. Aurius Rivendare fits into this category.

How the Death Knights Act
Despite popular belief, Death Knights are not cold, cruel, mindless beings. Take Thassarian for example. Death Knights are in most ways exactly how they were before they became what they are now. They search for a purpose, now that the Lich King is dead, but it's not hard to find one with the current conflicts going on between the Alliance and the Horde.

Death Knights are normally solitary in nature but might summon a minion if they prefer a pawn to use. Death Knights have varying morals, some willing to raise even the most holy of paladins from the grave as their minion.

Unique Qualities of Death Knights
The first generation's abilities are undefined as far as their necromantic powers, the second generation pretty much shares the same powers as the first generation. The Fourth generation possibly different powers.

A unique quality of generation three is that they require a Runeblade to use their magic, contrary to game mechanics a Runeblade is necessary for all their powers. And the saronite armor they don is mostly unpierceable (See Adamantine) and can absorb magics and reflect them back after awhile, this armor is exclusive only to the Undead who can resist Yogg'Saron's whispers. Death Knights have a constant addiction to slaughter and hurt others, sadism a common trait in their kind.

Generation two and four Death Knights do not require a runeblade to use their powers. Generation Three Death Knights need the Runes in their Runeblades to use their powers, although game mechanics doesn't show it. Razuvious tells you a Death Knight can't fight without his Runeblade. This is mainly because third generation Death Knights use Vrykul Rune Magic, while second generation Death Knight use Necromancy, Shadow, Blood or Frost magic.

Anyway, some generation two Death Knights (Those who got a Vampiric Runeblade) are extremely weaker without their Runeblade, as it stores their soul and power. This is the case of Arthas, but not all of generation two Death Knights use this kind of Runeblade or a runeblade at all.

Contrary to belief (Mostly due to game mechanics), Death Knights are Undead and cannot be living for long using their dark powers. Those who take up the Runeblade and use its powers eventually lose their lives to the dark magics and become Undead, as Arthas lost his soul to Frostmourne and was turned Undead. The other way a Death Knight could become a Death Knight other than to become Undead from corruption, is to be killed and raised by a powerful necromancer into a Death Knight. As Death Knights you can manipulate the life you siphon from others to make undead minions or pull your enemies to you, or just strangle them. The Death Knight being Undead is immune to effects of poison, disease, bleeding, as you need to be living in order for those things to really affect you. Death Knights also have a vulnerability to light and holy land as shown at Light's Hope Chapel where the land weakened the Death Knights of Acherus.

Allegiances
Death Knights usually have allegiance to the leader of their current faction. Those free from the scourge or Old Horde likely suit their own needs and crush all opposition, Death Knights when it comes to authority can range from devout to possibly traitorous and as far as personality range from irritable to cold and rational.

Races
Death Knights of the third generation are all the humanoid races. Each one being either a member of the Argent Dawn or a former warrior of the Horde or Alliance, or any other threat to the Scourge. The 2nd Generation consists of only humans and a few high elves or Dwarfs. The first of only human (Orc soul) knights.

The Worgen Death Knights are the former minions of Arugal who fled from him only to die by the hands of the scourge and be raised into their armies, but these are a rare commodity among the Death Knights, not being as abundant as the other races to be turned. Also, Pandaren Death Knights are extremely rare, as only a few of them were traveling around the world before the Lich King (Athas) was defeated.

Appearance
Death Knights typically have pallid skin and eyes of varying colours, from grey to black to blue. The first generation have red or grey or black, the second generation typically green, to black, to blue. The third generation typically has only blue eyes. Dwarf death knight would usually have blue facial and scalp hair.