|“You will have our eternal respect, as the greatest warriors to ever battle for Ninjago.”|
|— Arcturus to Lloyd|
General Arcturus was one of the generals of the Anacondrai and the leader of the Serpentine during the Serpentine War. Arcturus led his kind into battle during the ancient conflict, winning various battles in Jamanakai Village and Birchwood Forest. He proved relentless in his efforts to conquer Ninjago and defeat the Elemental Masters, until his adversaries found that the Sacred Flutes could hypnotize the Serpentine. As such, Arcturus' army was defeated and sealed away in various tombs, with his own kind winding up in a fang-shaped tomb in the Sea of Sand. Along with his fellow generals, Arcturus was found guilty of war crimes and banished to the Cursed Realm. Despite this, Arcturus' reputation was great enough that a celestial zodiac was named after him.
During the Second Serpentine War, Master Chen transformed his followers into fake Anacondrai, even going so far as to use Pythor to make the transformation permanent. Knowing that Arcturus and the generals wouldn't stand for Chen's actions, Pythor proposed releasing the spirits of the Anacondrai generals to curse Chen's army. However, this could only be done if the person who cursed them, Garmadon, sacrificed himself to take their place. Garmadon chose to do so with help from his son, Lloyd, freeing Arcturus and the generals; they proceeded to curse Chen's army, with Arcturus personally denouncing Chen before banishing him himself. Arcturus then commended Pythor for his bravery by restoring him to his normal size and thanking Lloyd for restoring peace between the humans and Serpentine, before passing on to the Departed Realm with his fellow generals.
Arcturus was General of the Anacondrai during a time in history when tensions were high between man and Serpentine. Upon hearing from Chen that the humans were planning for war, Arcturus believed they had no choice but to attack. He led the Anacondrai to victory in taking Jamanakai Village, thus starting the First Serpentine War. An alliance of Elemental Masters drove the Serpentine back to Birchwood Forest, but they soon countered with the aid of Master Chen and his cultists. Eventually, the alliance managed to defeat the Serpentine armies using the Sacred Flutes, sealing most of them away in underground tombs. However, Arcturus and the other Anacondrai Generals were put on trial—though they pleaded for mercy, Garmadon banished them to the Cursed Realm.
Decades later during the Nindroid crisis, Garmadon remembered facing Arcturus in battle, and Master Wu noted that a celestial zodiac had been named after him, but the two were unable to guess at the meaning behind the association of his name with the Overlord's project.
Project: Arcturus was eventually discovered to be a rocket named after the serpentine general and a constellation with the same name. The rocket carried the Nindroids, and the Ninja into space, where the Overlord hoped to obtain the Mega Weapon.
The spirit of Arcturus, along with his fellow generals, were freed from the Cursed Realm during the Second Serpentine War when Garmadon was sent there to take the Generals' place.
Upon being freed, they discovered Chen's impostor Anacondrai and cursed them instead. When confronting Chen, Arcturus denounced the pleading man as a liar, a cheater, and an impostor, and sent them to the cursed realm for his actions. Arcturus and the other generals thanked Lloyd for bringing peace between humans and Serpentine before restoring Pythor to his original size as a reward for his newfound courage. Arcturus and the other spirits of the Anacondrai generals soon headed to a portal to the Departed Realm finally at peace.
The Hatching (Flashback)
Wu told the Ninja about the Time Twins, starting with the Serpentine War and how the Serpentine attacked Ninjago.
Project: Arcturus was a rocket that was used by the Digital Overlord, Pythor, and the Nindroids to retrieve what remains of the Golden Weapons from a comet called Delta V. It is evident that either Pythor or the Overlord remembered him, and so named the rocket after him.
- 66. "The Hatching" (flashback)
- Arcturus is the only seen Anacondrai to have green eyes rather than red.
- Arcturus appears to use the same torso print decal as the 2015 Pythor Minifigure, only recolored in various areas.
- While he was still alive, Arcturus had black and gold markings with a green gem on his head, like the other Anacondrai generals. As a spirit, however, Arcturus appears to have no markings on his head, while the other generals do.
- Arcturus' name comes from a real star named Arcturus.
- He is one of nine Serpentine whose name is mentioned in the show. The others being Pythor, Skales, Skales Jr., Clancee, Acidicus, Aspheera, Char, and Mambo the Fifth.
- He and the other cursed Anacondrai generals are the only known ghosts to display the abilities of cursing mortals and making something (Pythor in this case) bigger/returning it to its original size.