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Synchronity Chain1

The Synchronity Chain (シンクロニティチェイン, shinkuronitichein?) is a gameplay mechanic in Ar tonelico II: Melody of Metafalica in which the party's two Reyvateils join together their Song Magic into a single, more powerful Song that can cause devastating damage to the enemies. This requires both of the participating Reyvateils to have a deep emotional connection to each other and to bring together the Harmonic Lines representing their emotions in the Harmograph during battle.


A Synchronity Chain is a rare phenomenon in the world of Ar Ciel in which two Reyvateils become capable of empathizing with each other to the extreme that they can feel the other's emotions and act on them, allowing them to join together the feelings they use to craft their Song Magic into a Song containing both of them.

Given the depth of the empathy required, few Reyvateils are capable of reaching this state, and it has been stated as well that the existence of Song Magic used exclusively during the Synchonity Chain state, known as Dual Songs, is anomalous in itself[1], causing these Songs to mostly be crafted when two Qualified make their passage through the Infelsphere layers, though there are exceptions that are instead crafted in a Reyvateil's Cosmosphere or in the Binary Field.

So far, this phenomenon has been observed solely in Reyvateils that have resided in the region of Metafalss.


A Synchronity Chain can be triggered in battle by making the Harmonics Curves of both Reyvateils join into a single sine wave, which is accomplished through the usage of Psychological attacks. Whenever the Psychological trend of the Emotion Indicator is fulfilled, the Harmonics Curves will be brought slightly closer, and after a few turns of doing so, they will finally join into a single golden line.

Synchronity Chain2

EX Song Magic Evolution, Luca and Cloche posing together and the replaced battle background.

The following turn, a short FMV will play showing the Reyvateils entering the Synchronity state, their sprites will change to a pose depicting their new emotional state and the battle background will be replaced by a swirl of green Hymmnos glyphs.

Once they have entered this state, players will have approximately 10 seconds to make use of it before the Synchronity Chain terminates itself automatically, during which they will have access to the following bonuses:

  • Unlimited MP: the MP gauges of both Reyvateils will no longer be reduced from having a Song active.
    Synchronity Chain3

    Emotion Indicator in Bonus Mode, showing another Burstech bonus gained despite the trend being full already.

  • Emotion Indicator in Bonus Mode: players will be able to fulfill the trends of the Emotion Indicator infinitely for as long as the Synchronity Chain lasts, allowing them to receive repeatedly the bonuses from doing so.
  • EX Song Magic Evolution: the current Song Magic being sung will automatically evolve to its EX level if it has been obtained. This is the level used exclusively by the Dual Songs and as such, can only ever be triggered under a Synchronity Chain.

Reyvateils can enter this state regardless of if they are singing Red Magic or Blue Magic, but there is no real benefit to entering a Synchronity Chain while singing a Blue Magic due to none of these Song Magic trees having EX evolutions, as well as the loss of Burst percentage from shifting from a Blue to a Red Magic Song.

Once the 10 seconds have lapsed, the Harmonics Curves will break off from each other and the Synchronity will end. If the Reyvateils were singing Red Magic during it, the Song will activate automatically upon the end of the Synchronity Chain.


While theoretically the player could trigger a Synchronity Chain right at the moment they have two Reyvateils in their active party at the same time, in practice this is not possible due to the way the Synchronity status is triggered in battle.

Before a battle starts, the game performs the following calculations:

Synchronity Increase Value = (Sync Rate - 25) / 2000;
Synchronity Reducer = -0,016667;

  • The Synchronity Increase Value is the amount that gets added to the Synchronity Reducer each battle turn, causing the Reducer to lose value with every passing turn.
  • The Sync Rate is a hidden value for the Reyvateils in the active party, and it has no relationship with the false Sync Rate value shown in the Heroine Topics chart. However, it is increased in the same way as the false value: finding Heroine Topics and watching them.

Then, at the end of each full turn, the game carries out the following calculation:

Sync Increase Reducer += Synchronity Increase Value;
if (Sync Increase Reducer < -1) Synchronity Increase Reducer = -1;
if (Sync Increase Reducer > 0) Sync Increase Reducer = 0;

  • The Sync Increase Reducer is a variable that causes the Temporary Sync Rate explained below to be reduced.

Therefore, if the Sync Increase Reducer turns out to be -1 or lower, the Synchronity Increase Reducer is given a value of -1, while if it is 0 or higher, the Synchronity Increase Reducer is given a value of 0.

Now, the reason for which the Sync Increase Reducer has an important role in the mechanics of the Synchronity Chain is due to the following process, which is triggered at occasional intervals (<1s) during battle:

Temporary Sync Rate += Sync Increase Reducer; (Temporary Sync Rate decreased if Sync Increase Reducer < 0)
if (Temporary Sync Rate < 0) Temporary Sync Rate = 0;

  • The Temporary Sync Rate is the Synchronization value obtained from triggering the Psychological bonus from the Emotion Indicator.

Therefore, what this process indicates is that if the Sync Increase Reducer is 0 or lower, the Temporary Sync Rate will continuously be reduced as time goes by.

And regarding the Psychological bonuses, the following is what happens when one is triggered:

Temporary Sync Rate += (Sync Rate + 100) * Psychological Level * Affinity / 4000;
if (Temporary Sync Rate >= 100) Temporary Sync Rate = 100;
if (Temporary Sync Rate > Maximum Sync) Maximum Sync = Temporary Sync Rate;

  • The Psychological Level is the number of turns the Psychological trend of the Emotion Indicator has been successfully met.
  • The Affinity is the qualification given to the relationship between the Reyvateil and her Vanguard. The following qualifications give the calculation the following multipliers:
    • Bad: 75%
    • Normal: 100%
    • Good: 125%
  • The Maximum Sync is the practical value of the Synchronity Chain and the max value that can be reached in a turn. Once this value reaches 100, it guarantees that a Synchronity Chain will be triggered in the following turn regardless of the status of the Reyvateils in the Defense Phase of the turn in which the value was reached.

However, the reason why it was said at the start of this explanation that triggering a Synchronity Chain from the beginning of the game is impossible in practical terms is due to the following: different Sync Rates have different Sync Increase Reducer values, requiring players to wait for more turns for the Synchronity Reducer to be zeroed out so they can start accumulating Temporary Sync Rate points to get it to 100.

The following table shows the number of turns that would be necessary to wait for the Sync Increase Reducer to go to zero:

Sync Rate Turns Required
0 to 25% Infinite (due to the Synchronity Increase Value being zero or a negative value)
26% 34 turns
27% 17 turns
28% 12 turns
29% 9 turns
30% 7 turns
31% 6 turns
32 to 33% 5 turns
34 to 36% 4 turns
37 to 41% 3 turns
42 to 58% 2 turns
59 to 100 1 turn

From the table above, it should be clear that triggering a Synchronity Chain with a Sync Rate of 25 or lower is impossible, and it doesn't become plausible as a battle strategy until the Sync Rate is at 37% minimum. Therefore, players desiring to put this mechanic to use should focus on increasing the Sync Rates of their preferred Reyvateils as much as possible.

The Sync Rate given by the Heroine Topics is given in detail in the following tables:

Luca/Cloche Topics[]

Topic Name Found Sync Rate Given
Croix's First Experience Phase 1 5%
About Life Extension Phase 1 5%
Luca & Reisha Phase 3 10%
Whatever Happens Phase 3 10%
Luca & Skycat Phase 4 5%
Cloche's Jealousy After diving into Cloche's Cosmosphere Lv 6 5%
Luca's Jealousy After diving into Luca's Cosmosphere Lv 6 5%
Troubled Family Phase 4 5%
About The Future Phase 4 5%
What A Girl! Phase 5 5%
Frustration Phase 5 5%
Flirting Quarrel Phase 5 5%
Is This the Last Time? Phase 5 5%
Mediocre Phase 1 1%
Innocent Eyes Phase 1 1%
Like Children? Phase 1 1%
Towel Balloon? Phase 1 1%
Refreshing! Phase 1 1%
Feedback Phase 1 1%
Working Well? Phase 1 1%
Let's Play! Phase 1 1%
Unlike The Name Phase 1 1%
Suffocating... Phase 2 1%
Isn't This Dangerous? Phase 2 1%
Bath Time Panic Phase 3 1%
Don't Put Too Much Phase 3 1%
Cynthia & Croix Phase 3 1%
Feel Good? Phase 4 1%
Ideal & Reality Phase 4 1%
Spring Elixir Phase 4 1%
XX Mood Phase 4 1%
Malpractice Phase 5 1%
XX Mood II Phase 5 1%
You Can Be Kind Phase 5 1%
Stinky!? Phase 5 1%
Enemy Roles? Phase 5 1%
Hell's Scenery Phase 5 1%
Every Part Of Your Body Phase 5 1%

Luca / Jakuri Topics[]

Topic Name Found Sync Rate Given
The Difference Phase 2 15%
About the Cosmosphere Phase 3 10%
How About Your Mom? Phase 4 15%
I'm Jealous Phase 5 4%
How Deep You Go? After diving into Luca's Cosmosphere Lv 6 5%
Thanks For Protecting After diving into Luca's Cosmosphere Lv 6 15%
Good Ambience Phase 2 3%
What a Disappointment! Phase 2 3%
Black Shadow Phase 2 3%
Let's Swim, Luca Phase 2 3%
The Legendary Duck? Phase 2 3%
Do Not Eat! Phase 3 3%
Bubble Bath Novice Phase 4 3%
That's Pretty Rude Phase 4 3%
Towns Destroyed!? Phase 5 3%
Tea Leaves Phase 5 3%
Similarities Phase 5 3%
Hazardous Zone Phase 5 3%

Cloche / Jakuri Topics[]

Topic Name Found Sync Rate Given
Gergo or Geugo Phase 2 10%
You're Brave Phase 4 15%
Not There Yet Phase 5 15%
Who Did it to You? Phase 5 15%
How Deep You Go? After diving into Cloche's Cosmosphere Lv 6 5%
Thanks For Protecting After diving into Cloche's Cosmosphere Lv 6 4%
Tsundere of Two Phase 2 3%
The Perfectionists Phase 2 3%
Are You Dizzy? Phase 2 3%
Let's Swim, Cloche Phase 2 3%
Sinking Gergo Phase 2 3%
Luxury's Not Enough Phase 2 3%
Don't Sleep in the Bath! Phase 3 3%
Makes Me Laugh Phase 3 3%
Extremely Strange, But... Phase 4 3%
Don't Feel Anything Phase 4 3%
I'm Philanthropic Phase 5 3%
Sincere Praise Phase 5 3%

Note: Heroine Topics not shown in the tables above will give no Sync Rate increases upon being watched.

Finally, as it should be evident from the calculations and variables shown above, meeting the Harmonics trend in the Emotion Indicator offers no direct benefit or changes when it comes to triggering a Synchronity Chain despite them causing the Harmonic Curves to lenghten.

However, it still is advisable to do so due to the higher level attacks the Vanguards can access upon reaching higher Harmonics levels, which will make easier to fulfill the Psychological trend of the Indicator in turn.


  1. Demongel: "Dual Songs like us can't exist without some level of mutual understanding, so they need to know each other deeply in a world like this. But then, normally you sing Song Magic by yourself. Dual Songs are abnormal in the first place."
  2. A Reyvateil's Melody Forums: Ar tonelico II Relocalization Project Subforum, Bugfixes and Hard Mode Thread - Synchronity Chain Mechanics Deciphering by RyleFury