Head Bitch In Charge is a woman with unquestionable and gets what she wants whenever she wants it.
She rules with an iron fist of bitchy-ness and fear.
Cross her = you die.
There can only be one Head Bitch In Charge in a workplace, school, team, etc.
If there are two or more, they either a) become besties and rule in a partnership or
b) claw each other's eyes out until there is only one left.