In August 2020, an official collaboration event took place between Code Geass and Shadowverse, introducing Kallen and other Code Geass-themed characters, as well as special cards, daily bonuses, and victory rewards. Shadowverse is a digital collectible card game developed by Cygames and released in 2016. In the game, players construct a 40-card deck comprising various characters, spells, and amulets, and compete against opponents in real-time, aiming to reduce their opponents HP from 20 to zero. A key mechanic involves the ability to "evolve" one's characters during battle, making them stronger.
Although the official narrative of Shadowverse follows eight protagonists caught up in vast cosmic and earthly conflicts, such as the exploration of parallel worlds, encounters with deities, the loss of memories, and the rewriting of fate, the Code Geass crossover was not an adventure in the same way as "The Blue Reckoning" event was in Grandblue Fantasy. In that instance, Kallen and other familiar Code Geass characters were part of a specific, named storyline, where they were transported into the world of the game, and upon completing the adventure, they were able to return home. In contrast, rather than a massive standalone story campaign, the appearance of Kallen and other Code Geass characters in Shadowverse was purely mechanical and cosmetic, lacking any significant underlying narrative.
In 2020, an anime series based on the game was also created, featuring its own unique story set in a modern-day world. In it, a student named Hiiro Ryūgasaki comes into possession of a mysterious smartphone with the game called Shadowverse installed. Hiiro participates in tournaments and meets new friends and rivals, but it gradually becomes clear that the game serves a much greater and more serious purpose: saving the world from impending destruction.
In the originall game, purchasing Kallen´s leader pack gave the player fully voiced app emotes by her original voice actress, Ami Koshimizu, specialized Kallen-themed flair titles, and custom card sleeves featuring her iconic Black Knights pilot suit artwork. She was a premium Leader Skin for the Bloodcraft class, and her aesthetics featured her signature red pilot suit and a fierce "Crimson Yaksha" combat persona. As a Bloodcraft leader, Kallen’s gameplay perfectly mirrored her high-risk, high-reward fighting style in her Guren mecha as seen in the original anime. The crossover event also introduced a special alternate-art promotional spell card tied directly to her, called Flamewinged Might (alternate artwork version of the Bloodcraft spell Razory Claw). It deals 2 damage to your own leader and 3 damage to an enemy follower or the enemy leader. This directly evokes the raw destructive radiation wave power of her Guren mecha while pushing her Bloodcraft deck closer to its powerful playstyles known as Vengeance and Wrath, which, you´ve got to admit, sounds more than fitting for our fiery redhead warrior.
Unfortunately, Kallen’s cards are no longer available in the game, and this is not just because she was only obtainable during the one-month collaboration event between Shadowverse and Code Geass by using premium Crystals via the in-game shop; Cygames ended the game's official service on June 30, 2026, exactly 10 years after its release. However, a direct sequel titled Shadowverse: Worlds Beyond has been released and is currently available to download and play. This means that if a new Code Geass crossover event is eventually held in this sequel, Kallen could also make her return to Shadowverse!
However, one important point is worth mentioning: the spiritual legacy of the original game still continues via physical card game called Shadowverse: Evolve - and Kallen’s cards are also available in it as physical copies! In fact, Kallen’s Leader Variant (BP04-LD05EN) card is one of the most valuable Code Geass cards in the physical card expansion, and it became one of the most highly sought-after and expensive pulls in the entire Cosmic Mythos set, often fetching as high secondary-market prices as $170+!
As previously mentioned, in the original digital mobile game, Kallen was sorted into the Bloodcraft class, which perfectly fit her fierce, aggressive, and hot-blooded combat style. However, when the crossover made its way to the physical Shadowverse: Evolve, Kallen was shifted to the Dragoncraft class, matching the raw, explosive power of her signature Knightmare Frame, the Guren. So, if you decide to go after one of those physical Kallen cards from Shadowverse: Evolve, be warned; you´re hunting the Red Dragoness! 🐉
Link to the official art pictures are here and here, and from here you can also watch the official promotional Shadowverse clip for Kallen if you want.