My secret side I keep hid under lock and key
Narcissa Black doesn't understand why she defies the Dark Lord; she just does. She'll tell anyone that will listen it's because she loves her family too much to allow them to be torn apart. But she's not so sure that it's the truth. She weaves so many lies that the line between the truth and lies have long been confused.
It's not like she cares anymore since she's lost everything that's ever mattered to her – her family, her control and her will. Without those, she's useless and hopeless. Her life spins out of her control and she's desperate to gain control of it again.
Maybe she isn't much different from Andromeda after all. She tries so hard to be like Bellatrix that she forgets that Andromeda is – and always has been – the better sister.