
「お前が守りたい物を俺が、命に替えても守る。」
“I'll protect what you wish to protect, even if it costs me my life.”
Arecos (アレコス) is one of the crew members of the NefeloMakion. He is Playable Character 3 (PC3) in the Hajimari no Kioku game. He is 23 years old during the events of the game. His crew position is listed as Combat Vanguard Officer (戦闘急先鋒担当) and his role is listed as Suicide Captain.
His short profile states that he is taciturn. He doesn't really like to communicate. When it comes to combat, Arecos becomes rampageous, as if he's a different person[1].
Arecos is from the Other Dimension, but has a counterpart STAR AnimaL in this dimension. As stated in the events of Twin Crew Stars, the animal Arecos in this dimension has the memories and abilities of the humanoid Arecos from the other dimension due to a special inter-dimensional communication mechanism.
In his detailed introduction[2], the following are stated about Arecos:

New friends!! Arecos, who came back together from Mars
Though normally he has a cool appearance,
his core does not waver due to the strong will that he has.
When we first meet it seemed like he already knew Astel.
Apparently he and Astel were old friends.[3]
Arecos in this dimension comes in the form of a red wolf-like animal. He was retrieved from the planet Mars. He likes strawberries. His hobbies are fighting and battle. His hex color code is #741C1D. He was found on Mars by Apolleon and Pollneu. He is the third of the NefeloMakion crew counterpart animals to join Astel in this dimension.
Arecos doesn't talk much and is usually described as “cool” whenever Astel brings him up[4]. Despite coming across as aloof, he is extremely loyal to Astel, and is considered trustworthy and reliable by his crewmates[5]. They ask him to run errands[6] and talk to him while he silently listens[7]. He is strong and charges in first during battle[8]. When performing in 3D, he is respectful, waving and bowing to the audience after he shows off his battle poses[9].
Prior to the events of Arecos' recruitment, it is mentioned that Phruity helps with preparing the food for the investigation team while Merck is in charge of keeping up communication no matter the distance travelled[10]. It is assumed they did not accompany the investigation team to Mars and Jupiter as both were in Astel's home during the dates while Apolleon wasn't on earth[11][12].
To retrieve Arecos, Apolleon and Pollneu leave for Mars sometime after September 27, 2022 (the date Apolleon comments on earth's weather, implying that he is still on the planet)[13]. It's possible that they leave on September 31, 2022, after the September Membership voice between Astel and Apolleon occurs on September 30, 2022[14]. September 30, 2022 is also when the first transition preview of Arecos is seen on a Splatoon 3 stream[15].
On October 1, 2022, Apolleon tweets about “memories that will last forever.”[16] Almost a week after this, previews of Arecos start appearing on October 7, 2022, signifying that Apolleon and Pollneu have arrived on Mars and have presumably met with Arecos[17]. They do not return yet, however, seemingly proceeding on to Jupiter from Mars. Apolleon, along with Pollneu and Arecos, arrive on Jupiter from Mars on October 19, 2022. Apolleon comments that Astel's house is now too small for the increasing number of inhabitants. He recommends that Astel move to get a bigger house[18]
Come October 21, 2022, it appears as if Apolleon and the others are still on Jupiter. He comments that Jupiter has huge clouds covering the sky, tornadoes are forming everywhere, and that there seems to be a lot of magnetic turbulence ahead. At this point, Apolleon also says that their group needs to be back by Sunday night (October 23, 2022)[19].
In the morning of October 23, 2022, Phruity prepares a fruit tart for Astel to eat before his stream later on in the day[20]. In the afternoon of the same date, Apolleon informs everyone that they have made it back to earth on time[21]. He posts another teaser for Arecos' reveal[22], but it is safe to assume that both Juke and Arecos have returned with him on this date as he has gone to both Mars and Jupiter by now.
During Astel's evening stream on that date, it is revealed that Phruity's fruit tart brought back Astel's memory of his crew from the other dimension. These memories are what he shares with his viewers via Hajimari no Kioku. In the same stream as the Hajimari no Kioku release to members, Arecos is introduced and a silhouette teaser for Juke is shown[23]. Astel confirms that there is another new individual in his home aside from Arecos, but they'll be introduced at a later date[24]. Juke is later introduced on November 4, 2022[25].

On November 5, 2022, a relationship chart[26] is posted on the Star AnimaLs twitter account. The listed relationships for Arecos are as follows:
When the animals split up into two groups to head to Uranus and Neptune[27] on November 10, 2022, Arecos goes with Apolleon and Pollneu to Uranus to retrieve Uratty. Juke, Merck, and Phruity, on the other hand, head to Neptune in order to retrieve Stridon[28].

During the events of Twin Crew Stars on December 7, 2022, Arecos goes with the other STAR AnimaLs and Astel to confront [The One Who Rules The Universe] Astel. Their departure is shown both in the Namae wo Yobu yo cover and in Twin Crew Stars itself[29].
In a flashback, it is shown that Astel assigned Arecos to be a front line fighter alongside Phruity and Juke. All three are told to maintain the front line and watch out for each other. While on the space train and travelling to the battlefield, Arecos can be seen beside Merck. He seems slightly disgruntled as Merck chatters on happily beside him. Later on, in the scene wherein Apolleon is downed by the enemy, Arecos can be seen beside Phruity.
After their victory, Arecos' 3D is revealed during the song おはよう (Ohayou) / Keno. His partner in this reveal is Phruity. When the song is done, Arecos show some cool poses to the audience, looking over his shoulder and getting into a fight stance. He then waves, sways from side to side, and then politely bows to the audience at Astel's prompting.
Currently, he resides in Astel's house[30].
