Resonant Battlefront (共鳴戦線,Kyōmei sensen?) is the sixteenth episode of CROSS ANGE Rondo of Angel and Dragon, it first aired in Japan on January 24, 2015.
Riza reports to Omiko that the reaction of the Aura is underground in the Misurugi Empire. Omiko says that it is time to recapture the almighty mother Aura and instructs Riza to go according to schedule, in synchronization with the opening of the Singular point. Finally, she says that this is the war that will determine the fate of the planet. Ange wakes up in a room and frees Tusk who had been tied up as they are visited by Salamandinay, Naga, and Kaname. Meanwhile, Vivian is having breakfast while talking to her mother, Lamia, and they are shortly joined by Ange's party. Ange suspects the food may be poisoned as well as the authenticity of Lamia being Vivian's mother. They go to a stadium at Salamandinay's suggestion afterwards and Ange is surprised that the place is still in almost perfect condition today. Kaname tells Ange that it is thanks to Salamandinay that the building, which is more than 500 years old, was able to be restored to good condition. Salamandinay then challenges Ange to a competition where if she wins, Ange must assist them in fighting against Embryo but if she loses, Ange is freed. They then compete through tennis, baseball, golf, and various other sports, and by so doing, they are able to develop a friendship. Salamandinay tells Ange that she is more than happy to that Ange is able to stand up to her. She displays an elated expression, which is something nobody else has seen her do. Sala tells Ange that what leaders have to do is to protect their citizens; while on the other hand, Ange expresses a negative opinion that opposes Sala's beliefs, creating a strained atmosphere between them. Meanwhile, Vivian, who is pleased with re-encountering her family, goes back to her parent's home with her mother for the first time in many years and they spend time together peacefully. However, their peace is forcibly put to an end as what appears to be an unstable singular point appears. In the face of this abnormal situation, Salamandinay moves into the offensive in an attempt to help the people, and Ange pilots the unfinished Villkiss to help Vivian. As the incident takes place in front of Tusk, he realizes that it bares the same hallmarks of Embryo that he had witnessed before when his parents were killed. Although she is confused, at the proposal of Ange, Salamandinay embraces the idea of negating the effects of her weapon, the Convergence Space-Time Gun which activates by singing a song called the Song of Stars, with the Vilkiss' Dimension gun and close the singular point. As this event triggers, Salamandinay realizes that she must act as a leader, and she pours her heart out to Ange, saying that they must increase mutual trust and that her mind is set on them supporting each other as good friends. The two acknowledge each other as friends and Ange gives Salamandinay the nickname "Salako" as she has problems pronouncing her full name. Salamandinay wishes to call Ange "Anko" (Red Bean paste) but the latter refuses.
When Ange and Salamandinay are at the vending machine. The toys inside include Haro from Mobile Suit Gundam, Culutt and the other leade robot from Choriki Robo Galatt, an F44A Crab Gunner from Fang of the Sun Dougram, Ryujinmaru from Mashin Hero Wataru (where Fukuda worked on storyboards and was also an episode director) and plush dolls of Kira Yamato, Lacus Clyne and Athrun Zala from Mobile Suit Gundam SEED and Mobile Suit Gundam SEED Destiny, two well known series that Fukuda directed.
The dots on twister-like game that Ange and Salamandinay were playing were based on the heads of Zeon mobile suits from Gundam. The blue (or rather, violet) dots resemble the MSN-02 Zeong, the grey dots resemble the MS-09R Rick Dom, the red dots resemble the MS-14S Gelgoog Commander Type and the green dots resemble the MS-06 Zaku II.
