Charlie was 33 when Roo attempted to kidnap her and make her its new host the same way it did Eve.
This is old for a human but for a demonic nephilim of her power it meant developmentally she still hadn't reached the toddler stage.
Her parents fended Roo off but they knew that if Evil had set its eyes on their daughter, it would not stop until it had her.
Or it was dead.
Lucifer and Lilith head deep into purgatory to fight Roo. At first it seems like their hits do nothing against it, its only when their powers hit the Entity simultaniously that they manage to cause injury.
This is why Roo wanted Charlie as its new host, as a child an angel and the first sinner, Charlie combined Infernal and celestial powers in a way previosly thought inpossible.
With Charlie as a vessel Roo would have no weakness.
Working in unison Lilith and Lucifer end Roo, the final blow is fatal for all 3.
The King and Queen of Hell live long enough to portal back to their daughter and bless her so that she might never doubt their love before turning to ash.
Hell much like purgatory or any divine realm is sentient to an extent and it loved L&L, the Morningstar's are its most beloved creators and rulers.
It feels L&L passing and feels their desire tk protect and care for their daughter and acts, latching onto her in a way that empowers and strengthens her but also binds Charlotte to the infernal plane.
Charlie is the Queen, anyone of infernal origin can feel it when in her presence, the urge to kneel and venerate.
Even as a small babe with a regent, everyone still recognised Charlie as being incharge, its part of why she was crowned and sworn in at 150 even when the people closest to her could tell that despite reaching her demonic age of maturity she was still growing and held the appearance of a child.
Hell was growing antsy over Charlie being 'denied' what was hers and wanted its last precious morningstar on the throne where she belonged.
The realm couldn't understand that Charlie was a child. It protected loved and cared for her but expected the same in turn. Hell knows that Charlie will make it great in ways that not even Lucifer and Lilith (cursed and restrained by their punishments from Heaven) were capable of.
It feeds her infernal half, building her power and growing the well that she could naturally use in a way that it couldnt for Lucifer who was already grown well Hell formed.
It shapes her power beyond the limits of what anyone dreamed was possible for a nephilim.
Her Celestial heritage also strengthens as her infernal and Divine powers feed into each other. Hell doesnt both to shape this aspect of her hut neither does it try to suppress it as without it she wouldn't be a morningstar.
Hell, but especially Pride bends to Charlies whims so she has to be careful when feeling anything to the extreme as joy causes the eternal stary night of hell to light up to near blinding levels and wrath has has the realm warping and breaking apart.
The connection between Hell and Charlie allows her to know everything happening within her realm - the eyes we see everywhere in the show were created by Hell to make things easier for her.
Even in the other rings, Charlies desires would over rule those of the sins should she ever desire it.
Charlie is to Hell what God is to Heaven.
Her strong connection is why Adam never tries to just up and take Charlie to hell and place someone else incharge until she's actually an adult.
Hell would riot and whilst he doesnt care about sinners and wouldnt be too bothered by hellborn suffering, Charlie would also be affected. Even visiting Heaven for brief periods is disorientating for her and she always ends up leaving due to Hell petulently tugging at her.
Theres also the fact it would uo end the war effort but that was honestly an after thought for him
