Supergirl has cast Angela Zhou to play the part of National City's top surgeon, Dr. Grace Parker.

Supergirl Season 3 has entered a brief hiatus, meaning the Reign plot is currently on hold. The series is sharing its slot with Legends of Tomorrow, with the break allowing the show's production to catch up. While that sadly means no new Supergirl episodes will be airing until April, behind-the-scenes news will continue to fascinate fans. Certainly the latest casting announcement will cause something of a stir.

RELATED: Supergirl’s David Harewood Was Shocked By Reign’s Actions

Angela Zhou is best known for playing Mei in Hell on Wheels, but will also be familiar to fans of the now-canceled Stitchers. According to Supergirl. tv, she's joining the cast of Supergirl. She'll be playing Dr. Grace Parker, a renowned surgeon in National City. Curiously, some sites are reporting that the character is named Dr. Grace Park, so it'll be interesting to see who's right. Perhaps there was simply some confusion created as the story spread around. Neither of those names correspond to an existing character from the comics, so those can't clear things up.

Reign and Supergirl in the episode Fort Rozz

Naming oddness aside, the bigger question is what role Zhou's surgeon will play in Supergirl Season 3. The current plot has seen the Girl of Steel battle against the terrifying threat of Krypton's Worldkillers. These powerful beings grew up with no knowledge of their Kryptonian heritage, but are now emerging as the most deadly foes Supergirl has ever fought. The last Worldkiller is still out there, and carries the name "Pestilence." TVLine has suggested that Angela Zhou could actually be playing this final Worldkiller. It would certainly be appropriate for a being known as "Pestilence" to have hidden as a doctor.

So far, the Worldkillers have all carried strong ties to imagery from the Biblical Book of Revelation. Reign herself, for example, has been paralleled with the "Beast" from Revelation 13. Pestilence is clearly a reference to the Four Horsemen of the Apocalypse, who are "given power over a fourth of the earth to kill by sword, famine, plague, and by the wild beasts of the earth." That reference certainly implies Pestilence will have a disturbing powerset.

The reality is that, at this stage, the role Zhou's character will play remains a mystery. The idea of the Worldkillers is a fantastic narrative device, a way of essentially allowing an actor to play not one but two characters. There would be a tremendous dramatic irony for National City's renowned surgeon to actually be the Worldkiller known as Pestilence. Only time will tell whether or not Supergirl will choose to take that approach.

MORE: Does Supergirl Season 3 Have Too Many Villains?

Supergirl season 3 returns to The CW on April 16.

Sources: Supergirl.tv, TVLine