Hel needs some minders guys. Both MASTER and APPRENTICE would basically serve the same function, bookkeepers/employees for her medium/bullshit occult store business. She'd treat them as friends, as she is the loneliest little goddess and she has none. Sex is unlikely from her direction, due to the whole half-corpse issue, but an awkwardsauce crush on a dude is entirely possible. Also, they must be able to put up with the constant stench of rotting flesh and the occasional bit of dead flesh. Both will be gifted with the ability to see dead people. But just a warning, once the dead know you can see them, they don't stop bugging you.

ALSO

GARM: Every good queen of the underworld needs her trusty guard dog.
GANGLATI and GANGLOT: Hel's servants.