The ancient being, known to many as Pennywise the Dancing Clown, had never considered the possibility of parenthood. It was a trans-dimensional creature, after all, and had always seen itself as above such mundane attachments. At least, until It's dusty sanctuary was invaded by inhuman children.
It seemed that every time it awoke from its slumber, there were one or two more beastly children in the decrepit old house. It all began in 1876 with little Georgie and his distrustful older brother. After some prodding, Pennywise learned the truth about why they were hiding in abandoned houses, feeding on the creeps that mistakenly assumed Bill, or his little brother, were easy targets. But that was a tale for another day.
A few decades later, their strange family grew when two zombie boys joined them in 1904. They were practically attached at the hip – as if they'd crawled out of the grave together. And, as it turned out, they had. Stanley, the child of a Hebrew man and a shapeshifting Broxa, came to them in 1929, but left only a decade later. It seemed that the only monsters who were willing to stay were the ones who did not age. Soon enough, the hybrid was replaced by the ghost of a chubby boy named Benjamin in 1957. Then came Beverly in 1984, who had turned to witchcraft to kill her abusive father, and Michael in 1985, who had the misfortune of being bitten by a werewolf.
Pennywise could have made a meal out of the last two, given that they were human… or human enough, to feed on, but it didn't desire to get on Billy-boy's bad side. It even turned a blind eye to the little love affair that occurred between the vampire, witch, and werewolf. The other two were human, or mostly human, teenagers, and Bill was an undead 18-year-old born in the 1800's – it was a relationship clearly doomed from the beginning.
In fact, it was quite amusing for the clown when the werewolf and witch decided to run away together once they were old enough to be considered adults by society's standards. And rather than hunt them down for hurting one of It's favorite blood feeders, Pennywise made sure to stick around to comfort Billy in any way IT could. After all, the pair would be dust and bones in less than a century, but Pennywise and his TRUE family would still exist in their un-aging state for many years to come.
Author's note: Going off the book dates for when Pennywise woke.