The final phase of Ar tonelico II: Melody of Metafalica's final battle, this time Nenesha and Infel are fighting together in order to make true their vision of the utopia. The Song playing during this battle is EXEC_over.METHOD_SUBLIMATION/. ~omness chs ciel sos infel.
Given their status as final bosses, it is to be expected that they have access to the best attacks and skills possible, as well as stats. Their elemental resistances also reduce all elemental damage to the point it makes all elemental attacks insignificant, and their skills are as follows: Sword Tune and Sword Chorus both hit a single character four times; Strongest Heal, which recovers around 21000 of their HP; Twin Circler, which hits all party members seven times; Explosive Ring; which hits all party members five times; Prism Light, which hits all party members six times and may inflict the Seal status; and finally Crystalune; which hits all party members ten times.
All of these attacks are executed very quickly, which makes them have very tricky blocking timings; and Prism Light is particularly problematic due to rendering the vanguards useless due to not allowing them to use anything beyond their Lv. 1 attacks, so it is advised to heal it if it gets inflicted on anyone. At this point, there's no point to hold back, so the player should use the best items they have at their disposal if the situation gets dire; and use the best Song Magic they can, such as Ar tonelico, Phantasmagoria, Infel Phira, or Meteor Shine; in order to take down both ancient Maidens.
Infel and Nenesha will signal the start of the second part of the battle when they use Strongest Heal to recover their HP upon losing 50% of it, during which they also gain access to Twin Circler, so it's at this point the player should focus all their firepower on taking them down. While Replekia can be used, it isn't advised due to cutting off the Song, but it shouldn't be really necessary to use it if the player has a well-prepared party. Once they have finished this battle, they are free to relax and watch the ending.