Drusilla Blackthorn is a former Shadowhunter and is one of the last known survivors of the Blackthorn family. Before her disappearance, she joined the rebellion against the Legion of the Star in Los Angeles in Thule.
- This character's history is identical to that of her alternate dimension counterpart up until just before the Dark War, where the timeline split and the following changes took place.
During Sebastian Morgenstern's invasion of Alicante in 2007, Dru was among the children hidden away in the Accords Hall. When Sebastian's forces overpowered the Nephilim, a group of warlocks opened a Portal to New York City but only let children through, forcing Dru and the others to leave without Mark and Helen.
The children sought refuge in the shelter set up by Magnus Bane and Catarina Loss while the battle continued in Idris. When the blight began to spread, Shadowhunters and their tools lost their angelic power, demons overran the streets, and warlocks turned into demons. The shelter fell within two months and the children had no choice but to try their luck on the streets.
Julian kept them together and, with Emma Carstairs, the young Blackthorns tried to get to a train station to California where they believed it was safe. Just before boarding, a large group of Endarkened and tried to stop them. Julian and Emma forced them onto the train while they kept the Endarkened at bay, sacrificing themselves so the children could get away.
Dru and her remaining siblings, Livia, Tiberius and Octavian, hopped trains and traded goods with other survivors to get through their days as they traveled to California. In Chicago, they met Cameron Ashdown and began traveling with him. They were devastated to find that, upon arriving in their hometown Los Angeles, the city and the Institute was under the control of the Ashdowns who had allied themselves with Sebastian's Legion of the Star. Cameron told them to flee, and they went back to their life on the run.
One evening while they slept on the street, a Shinagami demon grabbed Tavvy. Ty tried to fight it off but, without their tools, did not deal any damage. The demon struck and killed Ty and took off with Tavvy. Dru stopped talking altogether after the incident.
For a while, Livvy considered surrendering and joining the Legion if it meant that she and Dru would be safe, but before they could, Cameron found them and instead brought them to the Bradbury Building, where they joined an early incarnation of the rebel group that grew over the years.
Around five years later, Dru was lost during a scouting trip. No one ever looked for her because rescue missions were seen as futile and risky by many, including even Livvy, at that point in Thule.
Dru has the Blackthorns' signature dark brown hair and blue-green eyes. Unlike her siblings, she is curvy, round-bodied and quite tall for her age.
- Queen of Air and Darkness (first and only mention so far)