Evelyn was born to the Highsmith family in the 1930s. Due to the standing of her family and the time she lived in, she was raised to be rather snobbish, and developed a disdainful attitude towards Downworlders. At some point in her life Evelyn became the head of the London Institute.
In 2012 Evelyn housed the Blackthorn family in the Institute after an attack by Malcolm Fade on the Los Angeles Institute. She ignored them for the most part, having accepted them only because of her fondness for Arthur Blackthorn. The Blackthorns, in turn, kept her in the dark about their plans. The Blackthorns thought her rather odd as she often spoke to non-existent poeple, though it was later revealed that she was pretending to speak to the ghost of Jessamine Lovelace.
When Kieran was brought to the Institute following his rescue, Evelyn was outraged at the thought of having a faerie in her house and tried to have him escorted out; similarly when Magnus Bane arrived at the Institute with his adopted sons, Evelyn fussed about having a warlock in her house.
Evelyn is an imperious and old-fashioned woman who dislikes Downworlders and children.
Evelyn is a tall white-haired woman in her eighties who wears long 1940s-style dresses, and carries a silver-headed walking stick.
- Nephilim physiology: Being Nephilim, Evelyn possesses a variety of enhanced physical and mental abilities granted to her by the angel blood of Raziel in her veins and also by the angelic Marks of the Gray Book. This includes enhanced strength, speed, agility, stamina, and coordination, which continue to improve over time and practice.
- The Sight: As a Shadowhunter, Evelyn is naturally and easily able to see through most magical illusions and layers of glamour over reality.
- Runic magic: Due to the angel blood in their veins, all Shadowhunters are able to apply runes on their skin without any real danger. These Marks, in turn, give varied effects that serve to benefit the wearer.
- Use of heavenly weapons: As a Shadowhunter, Evelyn is also able to perform tasks unique to their species, such as the ability to use and call on the power of angels for their seraph blades, as well as to handle any heavenly weapons or objects with effect, which would normally not work for other species. In particular, these are tools made of adamas and forged by Iron Sisters.
- Walking stick: Evelyn possesses a silver-headed walking stick that she uses due to her advanced age.
Evelyn grew fond of Arthur during his stay at the Institute, and was surprised to learn he'd died.
- Lord of Shadows (first appearance)