Ilias & Adventure

 is the twenty-first chapter of the Trinity Seven manga series, released on September 7, 2012 in Monthly Dragon Age October 2012, and later compiled in the fifth volume on January 7, 2013.

Summary
As Hijiri happily greets Arata, Arata himself is surprised by the appearance of his cousin and childhood friend. However, Mira contronts Hijiri, revealing that her magic was not one that belongs to a human. "Hijiri" praises her for not being fooled, as expected from a member of Trinity Seven. Nevertheless, Mira launches a spell towards the imposter, but "Hijiri" is casually able to block her magic for the moment. Arata begs for the two of them to stop fighting, but Sora advises him to let them continue, noting that she would have stopped them if the girl was actually Hijiri. Determing that the timing was not right, "Hijiri" decides to retreat after bidding Arata a temporary farewell. Mira explains to a confused Arata that the girl was not a human, but instead, resembled more closely to Sora. Sora divulges that the imitator was another grimoire similar to her, the Ilias Fragment. In the past, during times when Hijiri was occupied with Magus business, the Ilias Fragment would often impersonate her and take care of him. After learning that Hijiri's grimoire has appeared at the supposedly destroyed Libel Academy, Mira decides to continue investigating on her own, assuming that Arata will go search for the girmoire. Arata remarks that Mira appears angry, although Sora explains that she is merely jealous, much to Mira's denial.

While the trio explores the location, Arata and Mira are confused the undemolished state of the buildings despite the reports stating otherwise. Sora indicates that the area was not created by "World Reconstruction" since only the Demon Lord Candidate is capable of using the magic. This information surprises Mira since that would insinuate that their location is the real Libel Academy. Sora confirms her suspicion, the Academy was not actually erased, but rather moved into a different dimension. Furthermore, she reveals that the school is encapulated in a barrier and that they were teleported within.

After further investigating, Arata comments that despite searching most of the premise, they have not encountered anyone else, including the other members of the group. However, Sora replies to her master that was not true before a group of creatures approaches them. Mira insists on elimating the impure presences, and begins invoking her magic. But instead, her clothes is suddenly stripped, much to her great embarrassment. Sora explains that Magus Mode has seeminly been restricted within the Academy, including Arata. As such, they are currently unable to defend themselves, with the exception of Sora. The grimoire encourages her master to escape with an abashed Mira. Although, because of Mira's embarrassment, Arata is forced to carry her closely, causing her to become quite meek. As the duo flees, Sora remarks whether or not he intends to create his own harem before confronting the creatures before proceeding to easily decimate the creatures. However, the Ilias Fragment appears afterwards, greeting her former fellow grimore. The two comments that the other's strength has not changed since. Nevertheless, Ilia asserts that regardless of Sora's power, they are still in her territory, but Sora remains confident as the grimoires prepare to fight.

Meanwhile, Arata and Mira discover that they are unable to leave due to the doors becoming locked. Arata jokes that Mira will have to spend the rest of life nude, although Mira meekly responds much to his surprise. Locating an empty room, Arata arranges Mira to wear his shirt, despite her shyness. After Arata praises her, the two begin discussing on locating the source of their predicament, as well as a way to escape the barrier. Arata questions Mira if there was an alternative to break free by defeating the originator, recalling of a similar situiation where he had defeated Arin's barrier by destroying the linchpin. Following Mira's confirmation, Arata then ponders the location of where such a linchpin would be set. Mira answers that there are two cases: a single point in the center or multiple points to form a magical circle. Upon learning of this, Arata decides to investigate the center of the Academy, then the perimeter alone to allow Mira time to recover her magic. However, Mira abashedly protests that she should come with him since he is unfamiliar with the area. Arata quickly relents, deciding to bring Mira along with him in the end. After Mira promises to return the favor, the two set out to explore Libel Academy.

Characters

 * Ilias Fragment as Hijiri Kasuga
 * Arata Kasuga
 * Sora
 * Mira Yamana

Trivia

 * Arata and Mira are surprised by the normal state of the Royal Libel Academy. In Last Crest & Problem Solving and Chapter 19, the Academy was declared to have been destroyed by an unknown Breakdown Phenomenon.
 * During their search through Libel Academy, Mira mentions that she had hoped to reunite with the others that had gotten separated from them after discovering the area was empy. This is a reference to Chapter 19 where they were originally supposed to investigate with Lilith and Akio until the warp device unexpectedly was interfered, casuing the group to split.
 * Discussing with Mira on a solution to escaping the Ilias Fragment's barrier, Arata recalls the events in Grimoire Security & Abort where he had managed to destroy Arin's barrier by destroying the linchpin.