Lumen

"You're not with Sumeragi are you? Then free her...free us both!"

- Lumen

Lumen, known as Morpho in Japanese, is one of the non-playable deuteragonists of Azure Striker Gunvolt alongside Joule. She is a projection of Joule's septimal power. Her Seiyuu is Megu Sakuragawa, the same Seiyuu she shares with Joule herself.

English Website Description
Lumen is a pop star promoted by the media-owning Sumeragi Group, and is currently the most popular idol in the nation. However, Lumen is but an avatar; a projection created by Joule’s septimal power, which takes on an entire form of its own completely separate from Joule. Unlike Joule, she has a very strong personality and is very much a free spirit. According to Lumen, however, this is just a manifestation of the person Joule truly wants to be. Even though the Sumeragi Group is promoting her as a pop star, she is in fact being used to locate other adepts that resonate with her ever-powerful Muse ability. These adepts are then found and captured by Sumeragi.

Exposition
Prior to the events of the story, Lumen is used as the Sumeragi Group's media icon. On the surface, she is a virtual pop star for the entertainment of the public masses. Unbeknownst to them, however, her Muse ability can track the locations of adepts throughout the world, and so the Sumeragi Group utilizes Lumen as a means of capturing and bringing under control the adept population—a venture known as "Project Muse." The resistance group QUILL thus initially intends to "deprogram" Lumen for the sake of the adept population's freedom.

Encounter with Gunvolt
The story opens with protagonist Gunvolt in an interrogation room, strapped to a chair and being tortured via electrocution by a Sumeragi officer. The officer reveals that Gunvolt is a QUILL agent on a mission to "silence the Muse," or Lumen; he also inadvertently reveals that Lumen is on a freight train being shipped away to a Sumeragi-sanctioned safe zone. Gunvolt then unleashes a flash of electricity, undoing his bindings and displaying his inherent affinity for electricity. He comments on the Sumeragi's officer's loose lips and thanks him for the electrical "recharge" before leaving the room and continuing his hunt for the Muse.

Gunvolt blasts his way to the end of the aforementioned freight train, only to discover that the hub of Project Muse is an adolescent girl strapped to a machine. Lumen then appears before Gunvolt as an apparition and reveals that she is a manifestation of the young girl's septimal powers. Under the presumption that Gunvolt is not with Sumeragi, Lumen asks Gunvolt to free her vessel, Joule, from the Sumeragi Group—implying that she and Joule are kept imprisoned against their will and are forced to play out the Muse Project. Moved by their tragic situation, Gunvolt ultimately resigns from QUILL and decides to free Joule and Lumen. The three then escape the Sumeragi freight train and begin their journey.

Six months later, Gunvolt, Joule, and Lumen are living together in an apartment in the ghetto district, Sinner's Row. While he is no longer a member of QUILL, Gunvolt continues to take on QUILL missions as a mercenary to "pay the bills;" Joule and Lumen assist him in these such missions.

Orbital Space Station Firmament
After Gunvolt has defeated six Sumeragi adepts, Sumeragi discovers Joule's location and sends a resurrected incarnation of their space master, Merak, to capture Joule and Lumen. On the night of Gunvolt's return home from his most recent QUILL mission, Merak confronts Gunvolt and Joule inside their apartment. He then quickly captures Joule and flees towards Sumeragi's orbital space station, Firmament, at which place Sumeragi ultimately and forcibly reinstates Joule's role as the Muse.

Gunvolt fervently makes a long trek to the pinnacle of Firmament, encountering and battling resurrected Sumeragi adepts—whom Gunvolt had defeated previously—in all the meanwhile. At the endmost room in Firmament, Gunvolt finds Joule strapped to a monstrous machine and, standing next to her, Sumeragi lieutenant and Project Muse executive—Nova. Nova boasts that the contraption before Gunvolt gives Sumeragi complete control over the Muse. He then summons a silent Lumen to demonstrate such control. Lumen's appearance remains unchanged, but her behavior no longer shows signs of her former, "mischievous" self and is replaced by cold, programmatic responses to Nova's beck and call. Nova then engages Gunvolt in battle, with Lumen fighting alongside him. She periodically creates protective barriers around Nova throughout this fight.

Upon defeat, Nova dismisses Lumen and praises Sumeragi for creating such a powerful fighter in Gunvolt. He then summons three glaives and fuses with them as well as with Joule to unleash his full septimal abilities. He transforms into a colossal humanoid abomination and engages Gunvolt in battle once more—this time, in space.

After utterly defeating Nova, Gunvolt retrieves an unconscious Joule from Nova's crumbling body and battle arena. Lumen—broken from her robotic trance—creates a protective barrier around Gunvolt and her vessel so that they can safely descend to the space station. Lumen's apparition appears weak, and she admits to overexerting her septimal abilities. After pleading to Gunvolt to look after her vessel, she withdraws to dormancy.

Joule seemingly recovers posthaste and begins descending Firmament with Gunvolt. As the two are walking towards the space-to-Earth elevator, Babel, they encounter QUILL's leader, Asimov. Asimov expresses pride in the two young adepts' endeavors in toppling Sumeragi. He then says that they are ready to "rule in the age to come." Asimov continues to reveal his ultimate ideal in wiping the entire human race to usher an age ruled by adepts. He had founded QUILL so that he could eventually attain this perceived utopia. Gunvolt and Joule firmly refuse to help Asimov achieve his ideal, to which Asimov responds by pulling out a gun loaded with special, septima-neutralizing rounds. He quickly dispatches Gunvolt with a special round and Joule with a regular round.

Epilogue
If Gunvolt completes Firmament (Idolatry) without wearing the Homemade Necklace for the majority of the stage, then the game ends after the cutscene following Nova's defeat. Re-loading the save file triggers a brief dialogue featuring Lumen, Joule, and Gunvolt. Lumen and Joule discuss the parallels between reality and fantasy, implying that the events of the ending achieved in this way may have been imagined.

If Gunvolt completes Firmament (Idolatry) while wearing the Homemade Necklace for the majority of the stage, then the game continues into an extended, optional stage: Firmament (Azure). After having her vessel shot to near-death at the hands of Asimov, Lumen completely merges minds with Joule. As Joule's body is sure to die, the Muse transfers herself to Gunvolt's mind and cures his nearly fatal wound, reviving him and augmenting his physical capabilities beyond normal capacity.

When Gunvolt recuperates, Asimov is already on his descent to Earth. The Muse and Gunvolt immediately track and confront him inside Babel's descent. Unimpressed by the miraculous revival of his comrade, Asimov affirms that he and the two adept youths are in great disagreement before revealing that he, like Gunvolt, is an azure striker. He then proceeds to fight Gunvolt and the Muse in a decisive battle that ultimately kills him.

Upon defeat, Asimov acknowledges his death but warns Gunvolt that, with the power that he has, he is doomed to live a life of endless fighting. He expresses regret for not instilling stronger revolutionist values in raising Gunvolt before falling silent.

Once the elevator reaches the Earth's surface, the doors open to Gunvolt's former QUILL comrades. Shocked and confused by the death of his commander, one of them demands an explanation as Gunvolt quietly steps out of the elevator. The Muse deeply understands Gunvolt's sorrow and quickly silences the confused comrade. As Gunvolt and the Muse step out into the dawn of a new day, the Muse comments on how they can go anywhere. Gunvolt and the Muse walk into the distance, "swallowed by the uncertain light of the rising sun."

Skills
While Lumen is never fought directly in-game, she can provide Gunvolt with the Anthem buff and can create protective barriers.
 * Anthem (ソング　オブ　ディーバ、Song of Diva): Lumen's special support skill. Whenever Gunvolt dies in-game, there is a small chance for Lumen to revive him back to full health and provide him with the Anthem buff, which gives him infinite EP. The stage's music is also overridden by "Reincarnation", with some exceptions.
 * Gunvolt can increase the probability of this event by talking to Joule on the stage select screen before embarking on a mission.
 * Gunvolt always has a passive Anthem buff in Firmament (Azure).
 * Barrier: Lumen's support skill in her fight alongside Nova. Lumen creates a barrier around Nova at the start of the fight. If Gunvolt fires a dart at the barrier, the barrier absorbs the dart and sends a large purple needle towards Gunvolt's location.
 * Gunvolt can dissipate the barrier by activating the Flashfield within its radius.
 * Lumen will recreate the barrier a couple seconds after it has been been dissipated by the Flashfield.