Veronica is an abrasive mage prodigy with a deceiving appearance. Though she may appear as a young child, in actuality she is much older; her stunted appearance is a result of an unfortunate encounter with one of the Lord of Shadows' monsters. Due to her brash personality, she often clashes with other characters and bickers with her fellow party members, even humorously stating that she relieves stress by arguing with Erik. This abrasiveness is extended towards herself, as she holds herself to an unrealistic higher standard. Despite this, she is still very caring, especially towards her younger twin sister Serena, whom she is very protective of; at the end of the day, she enjoys listening to her play on her harp around a campfire.
Both sisters are Keepers, a group of people who swore to protect The Luminary and aid him in the battle against Erdrea's evils. Furthermore, Veronica and Serena are the descendants of the sage Serenica, who accompanied Erdwin (the original Luminary) on his quest to defeat The Dark One. Since birth they have known of their destinies and are eventually called to action by the Elder of Arboria, who told them of her vision that The Luminary had reappeared in the world. The pair join the party after The Luminary rescues them by defeating the monster Jarvis. They eventually reach Yggdrasil to acquire the Sword of Light, but before the Hero can take it they are ambushed by Carnelian, who has been possessed by the evil sorcerer Mordegon. They and their lackeys subdue The Luminary and his friends before taking the Sword of Light and absorbing the heart of the Yggdrasil tree. Veronica sacrifices herself to ensure her party's escape as the world is plunged into darkness.
Sometime later, the party discovers that they can time travel to the past to undo Yggdrasil's fall and revive Veronica. With the help of the Timekeeper, The Luminary travels back in time and defeats Mordegon before he can head to Yggdrasil, allowing the tree to not be corrupted and Veronica to live. However, the timeline change allows for the awakening of the game's true antagonist, The Dark One Calasmos, who was destroyed in the original timeline. Eventually, Veronica assists The Luminary, the rest of the party, and the Timekeeper (who is revealed to be the alternate form of Serenica as a consequence for sealing the evil spirit) in defeating Calasmos once and for all. In the aftermath, she and Serena help The Luminary return the Sword of Light to Yggdrasil, while Serenica goes back in time to be with Erdwin.
Veronica is represented in the Hero's Comrades Spirit, which was added into the game as a part of the DLC Spirit Board in Hero's Challenger Pack. It is a Support Spirit under the Legendary class.
The battle uses seven different fighters, each representing a member of The Luminary's party from Dragon Quest XI; Veronica herself uses a Tiny Robin in her red palette swap, a reference to both her small stature and her being in the Mage class. The battle is a Stamina match with everyone having an increased Smash attack and weapon strength. The stage is Yggdrasil's Altar with the song "The Hero Goes Forth with a Determination" playing in the background. To win, all seven fighters must be defeated.
- Veronica's segment of the "Mii Fighter Costumes - Round 2" trailer make several references to Dragon Quest XI: Echoes of an Elusive Age:
- The Veronica costume is one of a handful of Mii Swordfighter costumes that does not use a traditional sword as a weapon. It is also the second costume to use a wand as a weapon, following the Ashley costume.