Black legion supplement is out in Australia, and so far, not much information has been leaked. But so far, what we know thanks to the guys from DakkaDakka, is the new Warlord Traits, and some artifacts.
Warlord Traits
1. Black Crusader
2. Re Rolls in the Chaos rewards table for the Warlord
3. A one use Flamer
4. The warlord gets the special rule It will not die
5. Attacks have a chance of causing Instant Death
6. Nearly units close to the Warlord get the special rule Stubborn.
According to the Chaos Warlord Traits on the Codex, this ones so far seem like a really good improvement. But opinions from people that purchase the codex already show disappointment. Apparently there are good items but they're really expensive...we will have to wait a little bit longer.
We will keep you updated as soon as we know anything!!