Gravelyn's existence was long kept a secret by her father Sepulchure as she was also the daughter of King Alteon's wife Queen Lynaria Alteon. When Drakath killed him, he heard Gravelyn's cries from the sky and shot down Sepulcure's flying fortress leaving it grounded. With her father gone, she was now inheritor of the entire Shadowscythe Empire.
Soon after, she agreed to strike a truce with King Alteon and his forces of good for help with defeating Drakath and the forces of Chaos.
When the lich Noxus and his creation Vordred stormed Shadowfall with their army, they confronted Gravelyn where it was revealed that he created her father's army and his flying fortress. Noxus then uses his magic to take control of Gravelyn's army. Gravelyn ended up Noxus and Vordred's prisoner when most of her armor is stripped from her until the heroes came to rescue her. Noxus had Vordred command his army to surround the heroes so that he can finish her off. When Sally contacts Noxus about ArcAttack being sighted in Doomwood and sends Vordred back to Doomwood, Gravelyn revealed that she had one undead loyal to her as the head of Chuckles knocks Noxus off of the throne and frees her. Gravelyn then commands her soldiers to let the heroes pass so that they can fight Noxus. Once Noxus was defeated, Gravelyn removed Noxus' head and placed Chuckles' head onto Noxus' body. She plans to have Cysero convert Noxus' head into a weapon for her to use. Before sending the heroes back to Doomwood to fight Vordred and intercept Artix, Gravelyn gives the heroes a special amulet that belonged to her father so that it will help them in the battle against Vordred.
Gravelyn awakens to find herself captive in the Plane of Darkness where Sepulchure is fighting Artix. It soon turns out to be a nightmare that Gravelyn has as the Noxus Head Staff tells Gravelyn that she probably had a vision of the future. Noxus then tells Gravelyn that her father was fit to lead the undead armies of the Shadowscythe as Gravelyn was surprised that Noxus knew Sepulchure before he became a Doom Knight and states that if she wants to know more about her father, she should look into the Forbidden Vault of the Necropolis. Seeing as it would require Sepulchure's helmet to enter the Forbidden Vault of the Necropolis, she lends Sepulchure's helmet to the players. Gravelyn is later captured by Chaos Vordred and Sally claims the Noxus Head Staff as Noxus orders Chaos Vordred to kill the heroes. When Gravelyn's last words were her wishing that her father was here, the tomb of Queen Lynaria Alteon grants her wish and revives Sepulchure. When Noxus orders Chaos Vordred to stand down, Chaos Vordred goes on the attack only to be easily destroyed by Sepulchure as Sally and Noxus bow before Sepulchure. Gravelyn detects that the Sepulchure present isn't the real Sepulchure. The tomb of Queen Lynaria Alteon states that Sepulchure was killed by Drakath where there is no coming back from death. Drakath ends up warping reality to make it look like the Sepulchure has returned from the dead.
In the alternate timeline caused by Drakath, Gravelyn appears at the point where she sees her father fighting King Alteon. When Drakath doesn't show up, King Alton dies protecting the players. When Sepulchure vanquishes Death enough to cause the recently departed to return as Zombies that obey Sepulchure's every command, Gravelyn shouts to the players to get out of the palace. When the Zombies break into Battleon, it is eventually revealed that Gravelyn is the Champion of Light (which explained by Gravelyn isn't undead like her father and how she lit up enough to hurt a Ghoul) as Sepulchure also learns this from his Doom Blade after Gravelyn left. This causes Sepulchure to go after Gravelyn so that he can open the portal to the Plane of Darkness.
Sepulchure shows up to challenge Gravelyn as an army of Angry Zombies and Zombie Dragons attack. The players see Sepulchure about to deal the final blow to Gravelyn. Sepulchure finds himself unable to kill his own daughter. Just then, Drakath appears and strikes at Gravelyn only for Sepulchure to take the hit. Gravelyn unleashes her full light powers to drive away Drakath. The Doom Blade then takes control of Sepulchure's body transforming it into Dark Sepulchure in order to finish the job. The players end up fighting Dark Sepulchure and managed to defeat him. Artix tells the players that a shadow creature can only be slain by the Blinding Light of Destiny as Dark Sepulchure gets up behind them. Gravelyn leaves her fight with Drakath and grabs the Doom Blade which she purifies into a weapon that destroys Dark Sepulchure and restores reality back to normal.
After reality is restored, Nulgath and Dage the Evil catch up to the group as Gravelyn tells them, Sally, and Noxus that the Shadowscythe Army will hunt down Drakath and make him pay for what he did to Sepulchure. Gravelyn then orders Sally to rebuild Vordred in order to use him against Drakath.
Gravelyn gets bored waiting for the next Chaos attack and summons the players to Shadowfall where they must decide the next option since King Alteon isn't up to taking the fight to Drakath. General Cynari and General Tibias assist the players into proving who is right. After slaying the Shadow of the Past, the players do their best to prove the Allegiance is strong and will help Gravelyn depending on if they are on the side of good or evil. Gravelyn then changes her armor and states that she will act weak as a way to fool Drakath.
Proud, graceful and powerful, she fits well into the role of being heir of the Shadowscythe. She will admit when beaten such as after her Dracolich fortress was thrown into a mountain. She is sad and angry about her father's death, and does not seem to be as evil as him. Gravelyn is perhaps the first real Affably Evil villain in the franchise, making it easier to work for her and alongside her. She calls the hero (you) as her closest friend, regardless of alignment. She also appears somewhat lamentful if the Hero is Good, showing that their beliefs may drive them against one another, even if they prefer not to. She is capable of compassion and a bit of a sense of humor. She truly cared about her father and also to those she deems her allies. She is also close to Chuckles, her first creation.