Updated Thu, Feb 21, 2008 by DarkFact
The Kurenai is a tribe of Broken who escaped slavery from the Murkbloods and Naga, and are escaping from their captors. They have two key outposts, one in Zangarmarsh called Orebor Harborage and one in Nagrand, called Telaar, which is the main hub for their quests. As Kurenai are Broken, and connected to the Draenei, they will only allow Alliance players to befriend them and enter their towns.
The Mag'har is the tribe of brown-skinned orcs who escaped the Legion's corruption the first time it came over the Orc Horde. They are a peaceful, shamanistic society and have their main town in the middle of Nagrand. These Orcs distrust the Horde initially, however, should you complete all their quests they will hail you a hero and make you bring forth Thrall in order to make an Alliance.
The Mag'har and Kurenai factions are the ones you will meet initially in the first two zones of the expansion (Kurenai in Zangarmarsh, for Alliance, or Mag'har in Hellfire Peninsula, for Horde). You will be questing for them mainly in your latter journey through Nagrand, which is a level 64 to 67 zone. While there's a few key differences, mainly in quests and lore, you will find that most of the reputation gains for both these factions come from the same places - monsters within Zangarmarsh and Nagrand.
Remember that you may also use Obsidian Warbeads (used for the repeatable quests) to turn them in for Consortium Reputation, so pick where you turn in all your Warbeads carefully to minimize faction-grinding!
Players wishing to gain reputation with the Kurenai in order to gain access to the epic Talbulk mounts will begin at Unfriendly with this faction. Quests done within Zangarmarsh and Nagrand will be a big aid to your reputation gains, however, you will still need to kill a lot of monsters and obtain Warbeads to boost it further toward Exalted.
In order to gain reputation with the Mag'har you will first need to complete the questline started in Thrallmar called "The Assassin", which leads you to the Mag'har's outpost in Hellfire Peninsula and opens the faction up so you're able to quest for them within Garadar in Nagrand. The Mag'har's exalted reward is also the ability to buy an epic Talbulk mount.
Repeatable Quest - Fierce Enemies (turn in 10 Obsidian Warbeads) -500 Reputation
Zangarmarsh - ~4000 reputation
Nagrand - ~10,000 reputation
Repeatable Quest - Proving Your Strength (turn in 10 Obsidian Warbeads) - 500 Reputation
Hellfire Peninsula - ~1000 reputation
Nagrand ~ 8500 reputation
* Keep in mind that should you complete all the quests for the Mag'har you will be treated to a special event where Thrall visits Outland and talks to the Greatmother.
Boulderfist Crusher: 10 reputation
Boulderfist Mystic: 10 reputation
Kil'sorrow Deathsworn: 10 reputation
Kil'sorrow Cultist: 10 reputation
Kil'sorrow Spellbinder: 10 reputation
Northwind and Southwind Cleft
Boulderfist Mage - 10 reputation
Boulderfist Warrior - 10 reputation
Murkblood Scavenger - 2 reputation
Murkblood Brute - 10 reputation
Murkblood Putrifier - 10 reputation
Murkblood Raider - 10 reputation
Laughing Skull Ruins
Warmaul Reaver - 10 reputation
Warmaul Shaman - 10 reputation
Warmaul Brute - 10 reputation
Warmaul Warlock - 10 reputation