Warning: The following contains SPOILERS for The Flash season 9, episode 3, "Rogues of War."A DC Comics villain originally introduced to the Arrowverse in Arrow was reintroduced with a major change that made them far more dangerous in The Flash season 9. The original Arrowverse Murmur was a ruthless gang leader, given the nickname after he sewed his mouth shut as a meditative focus. The new Murmur is far truer to the original DC Comics' character but still benefits from one major change from both the comics and the Arrow villain.

https://screenrant.com/the-flash-season-9-murmur-villain-arrow-change/