Last Crest & Problem Solving

 is the eighteenth chapter of the Trinity Seven series, released on May 9, 2012 in Monthly Dragon Age June 2012 issue and later compiled in the fourth volume on September 6, 2012.

Summary
As Arata becomes shocked over the sudden change in the environment, Lieselotte explains that her Final Crest, Baal Peor, created by the founder of Logos Art, Pythagoras, allows her to control the time of all matter other than herself, similar to the idea of "stopping time". Arata recognizes the concept, as stopping time is the dream of all boys. However, Lieselotte then attempts to strike a frozen Lilith, however is unable to affect her. Sora immediately understands that Lieselotte is uanble to interfere with anything other than herself. While Arata is disappointed by the fact, Sora questions their next move as Lieselotte can kiss him freely as long as she controls time. The reason that the two are able to move is because Lieselotte allowed their times to flow. Despite the situation, Arata recalls memories of Hijiri before inviting Lieselotte to come at him. Sora asks her master if he has a plan, although Arata states that he does not. But he does admit that he finally understands the determination Akio described for using her magic. Sora mentions his resolve is unless he can touch Lieselotte, but Arata notes that that part is her job which she quickly understands. Lieselotte interrupts them, asking Sora if she is ready to change masters, although the grimoire declines, stating that she prefers her current one. Nevertheless, Lieselotte proceeds to freeze the duo's time, rendering them immobile. However, the spell uses a majority of Lieselotte's magic, causing her to become tired before approaching Arata and kissing him. Afterwards, Lieselotte is estatic over having the Demon Lord's magic once more until she abruptly begins convulsing, eventually recognizing the effect from Mantra Enchant. Arata, suddenly able to move again, reveals a Mantra Enchant character on his tongue as Sora explains the character on his hand was a fake and that Lieselotte had absorbed the magic after kissing him, causing her to lose her magic. Sora confirms to Arata that his plan to move the magic to his tongue was successful. The two watch over a dejected Lieselotte as Sora inquiries the determination Arata had to put her in that state. Arata recalls the image of a young Akio praying after reciving her magic, before approaching and hugging Lieselotte. Arata then tells Lieselotte that her friends wishes for her to return to them, causing Lieselotte to be moved to tears. However, she states that she can no longer leave the stagnated world. Sora explains that there were risks involved in using the Final Crests; for Lieselotte, she would become unable to escape from the frozen time, the same fate as her predecessor. Arata worriedly demands the reason Lieselotte used such a dangerous spell; a surprised Lieselotte simply responds for her research, the same as his cousin, Hijiri. As Arata is shocked by the mention of his cousin, Lieselotte kisses him before expressing her gratitude, wishing that someone like him had been there to prevent her from becoming evil. Pushing him away, Lieselotte then gives her farewells, requesting him to apologize to Selina and Akio for her. As Logos Art bindings surround Arata and Sora to return them to the real world, Arata desperately tries to reach Lieselotte, promising to save her so that he may fondle her breasts, to which she complies. As he continues to struggle, Arata suddenly realizes that he is no longer in the stagnant world, accidentally groping an embarrased Lilith once more before thanking her for the please.

Afterwards in the infirmary, Selina learns of her sister's fate as Akio bemoans that Lieselotte received the same fate as her magic's orginator. Arata apologizes to Akio, although she does not hold him responsible before inquiring of Lieselotte's Demon King Element. Sora explains that she is caring for the elemenet since anyone else would lose control. Selina sadly accepts the loss of her sister, however Mira questions Sora the extent Arata processed Lieselotte's Logos Art magic. Sora reveals that they were very close, confirming Mira's suspicions. Arata and Selina are confused, while the rest of the girls quickly understands Mira's intentions as the leader of Grimoire Security orders Selina to help Arata master Logos Art to retrieve Lieselotte from her imprisonment. The girls agree that Selina should catch up to her sister so that Arata may save her. They also praise Mira for her thoughtfulness, although she insists that she only wishes to exact punishment on Lieselotte. As Mira and Akio leaves, Selina is stunned at the notion of reaching her sister, before agreeing to help Arata save her.

Meanwhile, Master Biblia observes the group from outside, pleased at Arata's growth and influence over the Trinity Seven. His assistant then arrives to confirm with him the destruction of Libel Academy, noting that Iscariot has begun making their move.

Elsewhere, admist the destruction and ruins of an town, a girl bearing resemblance to Hijiri is revealed.

Characters

 * Arata Kasuga
 * Sora
 * Lieselotte Sherlock
 * Lilith Asami
 * Yui Kurata
 * Arin Kannazuki
 * Akio Fudo
 * Selina Sherlock
 * Mira Yamana
 * Master Biblia
 * Assistant

Cameo

 * Hijiri Kasuga

Trivia

 * The Libel Academy is first introduced, as well as the introduction of Iscariot and reappearance of Hijiri