- "Echoing in the eyes. Brilliant to the ears. Sweet to the touch. Smelling of warmth. Unable to be appreciated by the senses. Astra. Only the light of one's astra can truly determine one's world."
- —Frederic, discussing astra in Eternal Sonata's ending
An astra is a jewel found within the heart of every person living in the World of Eternal Sonata. In some people, it glows quite brightly, but in other people it barely glows at all. Polka is known to have an astra that glows brighter than anyone else's in the whole world.
An astra cannot be seen, and therefore it is unknown what one looks like. However, agogos have the ability to detect a strong astra, and glow when they do.
- "There is a place, a place where I can make a real difference, now that the world is covered in darkness. It's a place that I have to illuminate, with the shining light of the astra that lies sleeping within my heart."
- —Polka explains her sacrifice.
Astra is first mentioned in Chapter 4, when Polka has a flashback at the inn on Sharp Mountains. In the scene, which shows Polka at a very young age, her mother Solfege tells her about astras and how they glow more brihtly in some people than others. She asks Polka if she thinks her astra is glowing, and Polka replies that she ate some cookies without asking, so maybe hers isn't glowing. Solfege teases her about the cookie theft, but then grows serious and states that Polka's astra is glowing too brightly for this world and it will lead her to a sea of never-ending darkness that she has to illuminate.
Astra is next mentioned following the battle with Fugue in Agogo Village, when March states that after Polka told her she saw a glowing agogo, she read a legend which stated that agogos are mirrors of the heart that reflect the shimmering jewel. Polka suggests that the jewel in question could be an astra, and Beat notes that if this is true, then their astras must be shining quite brightly to reflect so much light. Frederic, however, points out that it's really only around Polka that the agogos seem to glow.
Astras are next mentioned in Chapter 5, when Allegretto talks with Solfege in Tenuto Village. She asks him if he knows what astras are, and he replies that they're in fairy tales. She replies that many people think that they're just fairy tales, but they're actually quite real. She tells him that Polka has an astra that glows brighter than anyone else's in the world and because of this she must live her life chained to a tragic fate.
Later, the party speaks with a priest who tells them that the legend of the astra is housed within Aria Temple. They decide to pay a visit to the temple to learn more about it. They are confronted by Rondo, but defeat her, and then discover some writing carved on a wall, which states that "Only the light from the heart can illuminate the darkness" and that "...when darkness overwhelms, the heart that illuminates the darkness must give its life and all will be reborn."
In Chapter 6, Polka collapses as the party returns to Baroque Castle. Discusing the possible reasons for Polka's collapse, the Magic Researcher mentions the legend of the astra and how it may be connected to magic. Salsa suggests that if Polka's astra is glowing too brightly, they can just have the agogos absorb it. The party decides to find the Agogo Queen Mother in Agogo Forest. After finding her, they bring her to Polka and succeed at waking her.
Finally, in Eternal Sonata's ending, Polka states that there is a place of darkness that she must illuminate with the astra that lies sleeping her heart, just before launching herself backwards off the cliff.
The name astra may come from astral projection, or an out of body experience, when the soul and body separate. The souls of many mineral powder addicts separate from their bodies and reside in the Elegy of the Moon town, although it is not clear if the soul separates upon death, mutation from human form, or either.
Behind the scenesEdit
- "Oh, Polka. Your astra is glowing. But it's glowing far too brightly for this world. It's glowing so brightly that it is unconsciously leading you toward a deep darkness. One that must be illuminated."
- —Solfege to the young Polka.
- The video game series Kingdom Hearts features a similar concept, with those whose hearts are dark becoming "Heartless" monsters, and seven princesses who each have a pure heart with no darkness inside.
- The concept of astra is much more fully developed in the PlayStation 3 version of Eternal Sonata than in the original Xbox 360 version. In the original version, astra is only mentioned in the flashback scene with Solfege and Polka, by Polka in the game's ending, and by Allegretto in the XBox 360 exclusive sequence in which the characters speak directly to the player during the game's first set of closing credits.
- In the PlayStation 3 version of Eternal Sonata, Frederic may discuss astras while speaking to Emilia in the first set of closing credits, one of three possible sequences available during this set of credits. The choice of which sequence is used is apparently determined by which characters are used by the player, though the exact mechanics remain unclear.
- In the Church of EZI, a bonus dungeon in the PlaySation 3, there is a pillar that mentions astra in the Placid Parish area. It states that "When EZI created light, the birds and beasts became calm. When EZI created darkness, the birds and beasts became evil. And then, the birds and beasts came to know of the astra we all hold in our hearts."