|“||In the last extremity this weapon will not fail you; in the darkest hour this weapon will bring your enemy low.||”|
Isabelle Lightwood's whip is an electrum-wound tool that she uses as her primary weapon of choice. It is a rope-like weapon traditionally used to exert control over others through pain compliance or fear of pain. It can also be used to loop around anything and for exerting binding pressure.
In 2007, as an indirect gift to Alec, Magnus Bane enchanted the whip with a potion that "gave it a little extra kick," presumably enhancing its performance during times of dire need. Some months after, Isabelle was able to use the whip to sever Sebastian Morgenstern's hand.
The whip is made from gold electrum wire. With glamour, mundanes see it as a long, silver and gold bracelet on Isabelle's arm when not in use; in reality, it is the pattern of swirling lines of the whip, inked into her skin.
- The film and TV adaptations both depict the whip's glamoured or resting form as an actual silver bracelet.
- Charlotte Branwell of the London Institute during the Victorian era used a similar whip. It is possible that this is the same whip.