Privateer Press has been showing off several of Hordes' most powerful warlocks back before they were so powerful. They're the Level 0 Warlocks and the next one is ready for you to check out. It's Circle's Krueger the Stormseer.
From the article:
Leading up to the release of five early iterations of some of the most powerful warlocks in Immoren, we’re showcasing each of the rule sets currently in playtest in this series of Insiders. If you need to catch up, you can find Barnabas here, Makeda here, and Madrak here. Now it’s time for you to see Krueger the Stormseer.