Will Herondale, having to be cruel against his very nature every single day to everyone, terrified of Jem leaving, crying himself to sleep since learning of Jem and Tessa's engagement (every time Tessa sees him it is mentioned he is red-eyed), walking around London endlessly to outrun his own thoughts, unable to let anyone know. James Carstairs, dying and terrified it will break Will, growing weaker and hating himself for it, killing himself for fear of letting Tessa know her love isn't sustaining his life, unable to let anyone know. Tessa Gray, beaten and slapped, exhausted to tears in a prison, terrified for her brother and if he's dead, loving two people equally and having to hide it from both, unable to let anyone know. Gideon Lightwood, walking away from his family, hoping to be a better man that his little brother can look up to, wanting to save him from their childhood, in love with a woman that does not seem to want him, unable to let anyone know. Gabriel Lightwood, alone in a house with his father going mad, heartbroken at his brother leaving him, trapped by the Consul's blackmail, unable to let anyone know. Cecily Herondale, losing both her siblings in a matter of days, growing up alone and having to learn to repair the cracks left behind by her brother leaving, being angry at him for not thinking their family was worth it, unable to let anyone know. Sophie Collins, only a servant, her only wish to be a Shadowhunter being one which can never come true because she has a debt to repay, in love with a man with whom it can never work out, unable to let anyone know. Charlotte Branwell, her only desire to influence and help and protect being mocked and crushed by men, in love with a man that looks at her as a friend, unable to let anyone know. Henry Branwell, knowing things work different than what he's been taught, knowing he is right but cannot possibly explain and will always be laughed at as insane, in love with a woman that married him for convenience, unable to let anyone know.
The Infernal Devices understood loneliness like no other book I've read, the bone deep sense of being utterly alone even when surrounded by people.
