The Kurenai are a faction of Broken draenei in Outland. This is an Alliance-only faction, so Horde, try looking at the corresponding Horde-only faction, the Mag'har.
This Kurenai Reputation Guide will tell you how to get to exalted the fastest way. Why do you want to get exalted with these? Look at the rewards from their Quartermaster, Trader Narasu. Mainly people want the Talbukmount, their Tabard, or the part of the Diplomat Achievement to get exalted with them to get the title "<Name> the Diplomat" (You need to get exalted with Timbermaw Hold and Sporeggar too for this Achievement).
You start at unfriendly with them and have to do Quests in Zangarmarsh at the Orebor Harborage in order to reach Neutral and unlock the remaining quests.
Be aware that the Obsidian Warbeads are also used for Consortium reputation so think carefully on where you want reputation before handing them in.
First, do ALL the quests listed below. That will probably bring you close to Revered. The exact ending rep will vary due to the number of ogres and Kil'sorrow agents killed while completing the quests.
Now here's the hard part. Grinding for Obsidian Warbeads. They drop from any ogre in the zone, at a 30-35% drop rate. You should get an average of one bead for every three ogres killed. You can turn them in at Telaar for 525 reputation per 10.
If you obtain 50 Obsidian Warbeads, that's 2500 reputation. The amount of ogres to obtain that many beads is about 150. That's 1500 reputation from the killing, and 2500 reputation from cashing in the beads, 4000 rep total. If you manage to get to Revered with them from the quests, then you'll have to grind for about 260 beads, or approximately 780 ogres.
You get 10 reputation for each ogre you kill, so also consider that if you get one set of beads for every three ogres you kill, you've got about 300 rep (30 ogres) for every ten beads you collect, give or take.