Judith is the daughter of main character Rick Grimes (Andrew Lincoln), who was seriously injured in the last series.
She is being looked after by the rest of the survivors and with the help of Michonne (Danai Gurira) and others, she has turned into a strong and brave youngster.
Even though she is young she is able to handle weapons well and fight off Walkers if they come too close.
But in the teaser video for the new episode she is seen killing her first human, who seems to be a Whisperer.
READ MORE: Walking Dead season 10: Will Michonne return in episode 13?
In the four-minute-long clip, which is believed to be the opening scene, the survivors are surrounded by Walkers and are fighting them off before they get too close.
Daryl Dixon (Norman Reedus) uses weapons to take out most of the zombies while other survivors push them back with shields.
Ezekiel (Khary Payton) is in charge of looking after the children and he is seen running frantically away from the fire with a group of youngsters.
But he pauses and starts to panic as he cannot find Judith in the group, and he asks the other children where she is.
User Andre_tran commented on the video, which was posted on Reddit, saying: “Judith: First Blood, This is the beginning.”
Regime also commented on the video, saying: “Judith killed someone, what a legend”.
Fans were impressed with the intensity of the battle scene and are already excited for the episode to air on March 15.
Judith is one of the only main characters to outlive her comic book counterpart, with the first being Shane Walsh (Jon Bernthal) and the second Carol (Melissa McBride).
The series is based on the comic book series of the same name and fans are wondering how closely the series will follow the comics.
In the teaser video for the next episode, Carol is seen by herself standing at the top of a burning building firing arrows into the crowd of Walkers.
Gamma (Thora Birch) is seen trying to convince Lydia (Cassidy McClincy) not to go “back out there”.
She says: “You know what Alpha wants”. In the series Alpha (Samantha Morton) is Lydia’s mother but the pair have not crossed paths in a long time.
Lydia then replies: “I will never walk with her”. She abandoned her mum who used to treat her badly, making her feel like a servant instead of her daughter.
The Walking Dead season 10 airs on Sundays on AMC and FOX UK on Mondays at 9pm