Glottkin
The Glottkin are triplet-brothers and champions of Nurgle, who are the titular stars of the second volume of books to be released for The End Times.
Despite their allegiance to Nurgle, the Glottkin are actually Imperial by blood; the sons of a Nordlander father, Ollos Glotts, and his wife, a Life mage named Ethra Greenblood. The Glotts came to Norsica on a secret mission; by living peacefully alongside the Norscans of the fjords of the Sea of Claws, showing them the healing arts of the Wind of Life and more advanced methods for coaxing successful crops, they hoped to slowly break the chains of hatred that compelled the incessant cycle of raids and retaliations.
For some time, the two were welcome, becoming quite influential, but a jealous Norscan hag cut Ethra's finger with a cursed rusty knife during her pregnancy with her sons. Unable to break the hag's curse herself, Ethra pleaded with the gods to spare her children, and Nurgle took pity, curing the infection and allowing for the birth of three healthy boys; Otto, Ethrac and Ghurek. Each was healthy and hearty, the only sign of their future fate a birthmark with three lobes that each bore on their body.
Their efforts were doomed when a Nordlander force came to Fjordlingtribe land in 2506; the Glotts took up arms to defend their friends and neighbors, and the brothers saw their parents murdered by the Imperials. From that moment on, their souls belonged to Nurgle.
Ghurek devolved into a monstrous beast, an eating machine capable of swallowing men whole and then shitting them out as grotesque Chaos Spawn, to the point his own brothers took to calling him Ghurk and using him as a steed. Ethrac became a powerful sorcerer of Nurgle, using the black arts to slay and murder. And Otto turned his former scythe into a lethal killing tool as a champion of Nurgle.
They were chosen by Archaon to lead his second invasion during the End Times, allied to the Maggoth Riders and to Gutrot Spume. At the verge of victory, though, they were defeated, changing into fly swarms to escape death at the hands of a divinely empowered Karl Franz. Now the triplets are trapped in jars in Nurgle's attic, for Nurgle is very displeased with them...
On the tabletop, the Glottkin fight as a single Special Character Monster, since Otto and Ethrac always ride little brother Ghurk into the fray. They cost 810 points and use up a Lords slot. They have Movement 6, Weapon Skill 6, Ballistic Skill 3, Strength 6, Toughness 6, an insane 12 Wounds, Initiative 1, 5 Attacks and Leadership 10. They have the Nurgle's Rot mutation, and the common special rules Eye of the Gods, Impact Hits (D3), Mark of Nurgle, Poisoned Attacks, Regeneration and Terror. They also have the unique special rules of Ethrac Glott (they're a level 4 wizard using the Lore of Nurgle), Ghurk Glott (chose one attack per round; this one is S10 and Multiple Wounds (D6)), Otto Glott (gain +D6 attacks at the start of each Close Combat Phase), Lords of Nurgle (Glottkin and Nurgle-marked units within 12" re-roll failed charges, Glottkin always get the Aura of Chaos reward when rolling on the Eye of the Gods), and Pestilential Torrent (Strength 3 Breath Weapon that ignores armor, can only be used in close combat).
While this all sounds impressive, the issue with the Glottkin is that there's really nothing else going for them in a WYSIWYG fashion. Unlike the other behemoth model (Nagash), they have no other way to boost themselves or their forces (Like Nagash and his uber Lore of Undeath summoning triple the point's worth of spooky undead) and all they're ultimately worth is their bells and whistles. Taking the trio means that they'll need to be in constant combat in order to make back their points' worth, and their cost means that they're going to be a little pressed to find plenty of troops to guard them.