MAGNUS THE RED!
With the release of the new codex War Zone Fenris: Wrath of Magnus we got to be introduced to the daemon form of Magnus the Red. Magnus is a beast with 7s across the board barring strength (8) attacks (6) and ld (10). He has a 4++ save and can reroll ones and with certain items you can make it a 2++ save so good luck taking him down. One of the most major things is hes a psyker with mastery level 5 which means hes not gonna fail any of his manifestation rolls anytime soon. He does cost 650 points which might seem like alot intill you look at his weapon AP2, Soulblaze, Force, and Transmogrify (a 6 to wound causes Instant death and turns the slain model into a chaos spawn). Which if you take that into account too hes seems kinda OP and thats not including the formations he comes with. We havent been able to test him out in a game yet so we are going off of pure numbers so things could be differnt in an acctual game.