PvP in a Particular Level

The reason there are so many restrictions on creating your Death Knight ton is because Death Knights are considered a hero class. And as a hero class, you have many advantages such as starting your Death Knight to level 55 instead of level 1, able to play Death Knight of any race without Enchant Weapon, vacant land immediately. To play a Death Knight, you must have the wrath of the Lich King expansion, and also at least a level 55 or higher on a kingdom before creating your first character Death Knight.
Class Death Knight is the newest class of World of War craft that was added during the release of Wrath of the Lich King Expansion pack. All these advantages are what make such a class Death Knight attractive and fun to play whether an alt (alternative character) or the main character and cheap fast wow gold in the game. Just as warriors or Paladins, Death Knights are also a hybrid class that is capable of taking over a role. As a Death Knight, you are able to choose from two DPS spec, and a different tanking spec.
In addition, you can create one Death Knight Character per realm regardless of faction, but this should not be a problem because I do not see why you want to have two Death Knight anyway. Death Knights blood spaced are reservoirs, and Unholy / Frost Death Knights are spaced DPS and cheap wow gold in the game. However, if you want to play as a Death Knight DPS then the choice can be a bit more complicated as you choose between Frost and Unholy spec. Generally both frost and unholy Death Knight have very similar DPS in raids late in the game.
One major difference that must be considered is that as a Death Knight Frost you are able to choose between two weapons 2 a weapon with both hands or just exercise two one-handed weapons and wow gold us in the game, while Unholy Death Knight is limited to only two hand weapons. Like paladins, Death Knights are also a class warrior hybrid is able to use unholy, frost, and lots of blood. and a single class airline specific mounting.