Skreech Verminking
Skreech Verminking is a Verminlord special character who appears in "nu-White Dwarf" #49, and is probably going to appear in The End Times: Thanquol book when it finally comes out.
Whereas most Verminlords are explicitly compared to Greater Daemons, Skreech Verminking shares more in common with a Daemon Prince in that his essence was originally mortal. When the Skaven first warred against Nagash, the Council of Thirteen eventually managed to slay the ambitious founder of necromancy. Though initially Impressed by this, the Horned Rat got pissed when the skaven went right back to their petty rivalries instead of claiming dominion of the world. In rage, he plucked the lords of decay from the mortal world and threw them into a dark pit in his realm, where they languished for centuries. In the pit, they could do nothing but blame each other and feed on the scraps of failed plot thrown at them by the horned rat. Eventually, the horned one realized that they had still accomplished much, so he dug them out of pit. By this point they were a horrible mewling mass of 12 rats fused into one, so he blasted the twelve Lords of Decay with a single searing bolt of black warp-lightning, sweeping up their souls and merging them into a singular entity. Thus was born Skreech Verminking, greatest of all verminlords, the purest representation of all the spiritual aspects of Skavendom and truest avatar of the Horned Rat.
On the tabletop, Skreech Verminking has the exact same attributes as any Verminlord, but costs a good 150 points more. His "affinity spell" (the automatic spell he starts with and which he can re-roll failed casting attempts for) is The Dreaded Thirteenth Spell, and he wields the Doom Glaive (Multiple Wounds D3) and Plaguereaper (Always Strikes First) magic weapons, though he only benefits from one in each Close Combat Phase.