This article contains plot details about events that occur later in the game.
Solaris is first encountered outside the gate at the Grand Stairway, although he is not named until later. He tells the player about the history of Reborn City, revealing that Reborn's very core lies behind the gate, while expressing distaste at the city that has been built above it, vowing to bring together the four keys needed to open the gate so that "beauty can be restored to the world".
He then promises the player that they and Victoria may safely leave the Grand Stairway before himself making an exit.
Solaris next appears in a small room in Blacksteam Factory, where he remarks that he didn't expect to meet the player again, before opening up a trapdoor underneath their feet. He is seen with ZEL not long afterwards in a room housing Team Meteor's PULSE Muk, which he uses to distract the player so that his Garchomp can kill them using Dragon Rush, although Amaria thwarts this attempt by using her Kingdra to freeze the Garchomp with Ice Beam, after which he returns it to its Poké Ball.
Solaris then reveals that the purpose of the PULSE Muk, as well as that of the other PULSE Machines, is to drive out the citizens of Reborn City in order to revert it to its former state of desertion. He soon takes an interest in Amaria's Sapphire Bracelets, however, after which she engages him in battle in order to defend them, ordering the player to deactivate the PULSE while she does so, an effort which ZEL attempts to obstruct.
Solaris's identity is finally revealed by ZEL as the latter apologises for failing to stop the player from deactivating the PULSE Muk, after which Solaris commands his Tyranitar to attack Amaria with Superpower - badly injuring her - before giving the order for Team Meteor to retreat.
Solaris is next encountered alongside Taka and Cal when the player, Cain and Victoria confront them atop Pyrous Mountain in the hopes of deactivating their PULSE Camerupt. With Cain already overwhelmed by virtue of having been outnumbered, Solaris orders Taka to fight Victoria while he engages the player with just his Garchomp - regardless of the outcome of this battle, the story progresses with no major differences.
Once Solaris's battle with the player is complete, Kiki arrives, attempting to destroy the PULSE with her Medicham - Solaris instructs Solaris then orders his Garchomp to execute Kiki, successfully killing her in one swift blow.
After leaving Pyrous Mountain, Solaris is not seen again until Team Meteor's attack on Fiore Mansion, where he is accompanied by Sirius, Fern and Blake in his attempts to retrieve the Sapphire Bracelets. Upon entering the house, he is met by Florinia, Julia and the player, at which point he states that he will leave peacefully as long as the Sapphire Bracelets are ceded to him - an ultimatum which is rejected wholeheartedly by Julia.
In light of Julia's declination, Solaris orders Team Meteor to attack - after a pair of grunts fail to defeat Florinia and the player, however, Solaris commands Fern and Blake to take them on instead.
Solaris's next appearance is during Team Meteor's attack on Agate City, where he is accompanied by Sirius, as well as Taka if the player decided to fight the latter in the Water Treatment Center - in either route, Solaris demands to take on the player alone once they and Hardy have defeated the team's grunts.
After the player defeats Solaris, Sirius remarks that "perhaps a soft bite runs in the family", to which Taka responds by attacking Sirius with his Chatot. With the Team Meteor grunts forced to take on the heroes themselves, Solaris in turn reprimands Taka for his defiance, after which he flees to the north with Sirius and Solaris in tow.
After the player defeats Solaris, Sirius taunts him about his failure, eventually revealing to him that Taka was killed as a result of Lin's actions. Sirius then begins lambasting Solaris's leadership abilities, declaring himself more fit to lead Team Meteor, after which Solaris flees to the north.
Solaris and New World Orderly John are fought in a Double Battle format. If the player beats Solaris at Pyrous Mountain, this battle is fought alongside Julia - if not, it is fought alongside Florinia.