Arista

Arista are green Crystals featured in the Gundam Build Fighters. While most of the details are still shrouded in mystery, it is known that connects to Arian and Plavsky Particles.

History
Arista was first introduced when Reiji gave one of the two gems he had to Sei, claiming that if Sei were to make a wish on the stone, Reiji would come to grant his wish. This is proven true as Sei was about to lose a duel with Susumu Sazaki's Gyan; when Sei wished to avoid losing, Reiji was brought into the Iori Hobby Shop's battle room and take over control of the Build Strike. In light of these events, Sei kept the gem on his GP-Base, whereas Reiji had the other in his bracelet.

The crystal was brought up again when Reiji confront Chairman Mashita, who in his mind (and thus to the audience member) proclaimed that the ownershipof the crystal indicated he is a crown prince of Arian.

Sei transfered the gem into a pendant which he had China Kousaka gift to Aila Jyrkiäinen before his and Reiji battle with the operator of the NMX-004 Qubeley Papillon (GBF: Episode 21). During the battle Aila came under stress given the conflict betwen her wish to avoid fighting Reiji and the influence of Team Nemesis Embody System making her fight (as well as giving her pain). This caused her Arista to trigger the same wish effect Sei had previously caused.

As a result of the trigger, the level of Plavsky Particles in the arena increased dramatically, with the particles (including all Aristas known to date) glowing into an orange light that confused the guests and managers of the tournament. Reiji and Aila either developed a mental link, or were transfered to a subspace where Reiji became aware that Aila was forced to fight, he therefore convinces her to abandon the use of the Embody System and leave team Nemesis, offering Sei's house as shelter.

It is also during this event that it is revealed Chairman Mashita has his own Arista, which is seen by Baker as it reacts with the other two. It is kept inside a Pocket Watch. It is from the CEO's description of his stone that it's name, Arista, is made known.

Following the battle, Nils Nielsen borrows Reiji's gem and has it studied (GBF: Meijin vs. Meijin). After managing to obtain better examination hardware from Japanese Universities he confirmed a previous suspicion that the Arista was, in fact, a Plavsky Particle Crystal.

Known Aristas
All three Aristas display the ability to respond to the presence and activation of another; in doing so, they shine brightly in a golden hue. A side effect of this phenomena is that nearby Plavsky Particles, such as the ones in the World Trourmanent Battle Stage, have a sudden increase in number. This is relevant as the stages do not have the means to produce more Plavsky Particles (given the fact they are dispersed, not created, when the machine is activated).



Like most pieces of Unknown Phenomena in the Gundam Series, Seed Factor and Newtype abilities being a prime example, Aristas tend to display their powers when the emotions of an user reach a significant level. An evidence of this is seen in episode 21, when Sei gets frustrated over Reiji's anger at Aila and Aila's apparent betrayal, causing his Arista to Shimmer, revealing the Particles in It.

It was brought by Reijibrought two of them when he arrived on Earth from Arian, one which he carries in his bracelet, and one which he gifted Sei, who had it transfered to Aila on Episode 21. The third one is held by CEO Mashita of PPSE.

Reiji's Bracelet
According to Chairman Mashita (GBF:Fighter's Radiance) the Bracelet, and It's Arista, are an heirloom unique to the Royal Family of Arian (and in this particular case it's Crown Prince: Aria Von Reiji Asuna). It's importance is exacerbated by the fact Reiji never took it off his arm, not even during sleep or for taking a dive on the beach. Despite this fact Reiji shows no hesitation to give Nils the Arista Stone even tough he, above anyone else, should know it's importance.

It is hightly probable Reiji's ability to travel between Arian and Earth might be connected to the Royal Bracelet. This is in light of the following evidences from the series:

There are, however, arguments which discredit this line of thought Arguments one and two, of the above can be discounted if it is assumed Reiji lied about not being able to take Sei, as well as having found the key to his transportation rather than having learning how to use it. Unlikely, as Reiji has been known to speak his mind and not lie, even when doing such would be better for him (Gundam Build Fighters Episode 2 ).
 * 1) Reiji himself claimed that he found a means to come to Earth in the Palace Treasury (GBF:[[Full Package]).
 * 2) There is no other known object in the Build Fighters series with advanced/magical properties that would allow such travel.
 * 3) The only other person to even aknowledge the existence of Arian (and Reiji's Status) is also the holder of an Arista
 * 1) The second Arista (Emblem/Necklace) aledgedly cannot be used for such travel.
 * 2) Being a Royal Heirloom, Reiji most likely had it on him long before he could "Find" the bracelet in the Treasury, otherwise it is unlikely that Mashita would have been able to see Aria von Reiji wearing it.
 * 3) Aside from the bracelet, Reiji also has the sunglasses he wears on his head at all times (again, including sleep/night events), but never actually uses over his eyes, despite instances such as when he was in a very sunny beach. Which might imply they have a yet to be disclosed use.
 * 4) The red light used in Reiji's transportation is different than the Golden Light of the Arista as it became active.

Sei's Emblem / Aila's Necklace
The twin to the gem in the bracelet. It was brought to Earth by Reiji, and given to Sei after the later had covered for Reiji's accidental stealing of Bread(GBF: Episode 1). Sei kept the Arista with him after using it's power to summon Reiji to take over the control of the GAT-X105B and placed it in the emblem slot of the GP-Base (Curiously, the only person in the series to costumize the device in such a fashion).

Sei saw fit to remove the stone and give it to Aila in hopes that it would allow her wishes to be conveyed to Reiji (GBF: Episode 21). Either he or China Kousaka had the gem embeded in a necklace, China then gave the necklace to Aila (in order to avoid raising suspicion from team Nemesis) and Nine Barthes inadvertedly set up his own fall by having Alia wear the gem for the battle.

It presumably cannot be used to send a person to Arian, otherwise Reiji would have been able to prove his origins to Sei (A tale which, so far, no one Reiji told the story believes) by using it to take Sei to Arian. Another possibility is that Reiji does not know of items, other than his own bracelet, that allow transpot between the two worlds.

Despite the fact Aila has it in episode 21, she is not seen wearing it in the next episode.

Mashita's Pocket Watch
The third Arista to be revealed, and the only one to be named as such. Like the other two it resonates in the stadium when Aila  makes her wish (GBF: Episode 21), which is when Baker discover's it. However, it did not take Chairman Mashita to the same subcountious space Reiji and Aria were taken to, most likely because he refrained from touching it when it became active (Reiji and Aila both wore and did not remove their own Aristas when they became active). Other than that, it's uses are unknown, tough it is certain that it has ties to PPSE's own means to produce the comercially used Plavsky Particle, which are kept under heavy lock and key.