Lost Rune & Luxuria Girls

 is the fifty-third chapter of the Trinity Seven manga series, released on April 9, 2015 in Monthly Dragon Age May 2015 issue and later compiled in the twelfth volume on August 8, 2015.

Summary
After the opposing teams prepare for their next move, Arin with Yui's support and Hijiri with Lugh's support stike one another which causes a Breakdown Phenomenon to occur. Although the stadium begins to break down, Yui's barrier helps protect the crowd from being affected. At the same time, Hijiri and Arin starts to disappear but the two assure Lugh and Yui that the situtation is fine since they can rescue Arata before completely disappearing along with the Breakdown Phenomenon. Afterwards, Lieselotte signals Yui to continue before she hitting a surprised Lugh, causing the thief to sleep. As such, Yui's team is announced as the winner of the match before the tournament is halted to repair the stadium.

Abyss Trinity and the Headmaster discuss Arin and Hijiri's plan to enter the spirit world in spite of the danger.

Elsewhere, Anastasia-L, along with Arsha, apporaches Lilith and Mira and introduces themselves. Since their match is currently postponed, Ana requests a conversation with Lilith while also revealing her knowledge of Lilith's past. However, Mira is still furious with their capture of Arata, Akio, and Levi, and their attempt with Lieselotte, but Lilith nontheless accepts with the condition that she choose the location.

As such, the group find themselves relaxing in the academy's hot springs much to Arsha's surprise. Lilith explains that they have lately been socializing nude, but she also does not consider Ana to be an immoral person in spite of her actions. Nontheless she believes in Arata which Ana comments that the two have a strong bond. Subsequently, Ana reveals that she loves Arata and inquiries of Lilith's feelings, much to the Trinity Sevens' embarrassement, although she states that Lilith can give her answer during their match. Regardless of the outcome, the two resolve to enjoy their match, but Arsha nevertheless remains uneasy.

Upon completion of the stadium, the second match between Anastasia-L and Arsha against Mira and Lilith begins. Ana starts the battle by summoning three of her Demon Lord Knights, including Astral Trinity.

Characters

 * Hijiri Kasuga
 * Lugh
 * Yui Kurata
 * Arin Kannazuki
 * Master Biblia
 * Abyss Trinity
 * Lieselotte Sherlock
 * Selina Sherlock
 * Lilith Asami
 * Mira Yamana
 * Anastasia-L
 * Arsha

Flashback

 * Levi Kazama
 * Akio Fudo

Trivia

 * Anastasia_Arata_Lieselotte_cover_Monthly_Dragon_Age_May_2015_MZ.jpg cover of Monthly Dragon Age May 2015 issue featured Arata and Lieselotte, as well as the eleventh volume cover featuring Anastasia-L, which was also released on the same day as well.
 * Continuing from the previous chapter, Arin and Yui continue their match against Hijiri and Lugh.
 * Mira is initially suspicious and hostile towards Anastasia-L and Arsha due to their roles in capturing Arata, Akio and Levi. Arata fell under Ana's control in Logos Mystery & Lost Master while Akio and Levi were defeated and imprisoned by Arsha in Backstage & Chrono Gemini.
 * Arsha also remarks that they were unfortunate to capture Lieselotte, referring their failed attempt in Chapter 47.
 * Anastasia-L reveals that she knows Lilith's true name, Lilith Azazel, referring to the Trinity Seven's origins as the daughter of Abyss Trinity from another world. The nature of Lilith's lineage was first revealed in Forbidden Element & Aeshma.
 * Lilith notes that their circle have been socializing nude lately which causes Mira to recount their experiences in the hot spring from Hot Spring & Alchemist.