Prefaces his text with .Except the prefix change, quirk is basically the same as Equius's. Censors profanity with glitches. Seems torn between talking politely and swearing e%cessively. Replaces x and "cross" sounds with % and loo with 100. Capitalizes words relating to STRENGTH. Normal punctuation, but omits end punctuation. Occasionally makes pony/horse puns (can't -> canter, etc.)
Arquiusprite is Dirk Strider's sprite after being prototyped with the remains of Equius Zahhak by Gamzee Makara and subsequently with Lil Hal by Dirk. His name is a combination of AR for Auto Responder and Equius. Similar to how other B2 sprites have a combination of the zodiac symbols of the two trolls used to prototype the sprite on them, Arquiusprite's symbol is the Sagittarius sign, with the bow replaced by the shape of Lil Hal's "body".
Unlike Tavrisprite and Erisolsprite, who both experienced a great degree of self loathing after having their component identities merged, Arquiusprite is ecstatic upon being created, experiencing relatively little conflict between the two personalities. Equius Zahhak seems to be delighted by the amazing speed at which his partly-computerized mind works, while Lil Hal is thrilled by Equius's particularly vigorous body and STRONG emotions. The only point of conflict between them seems to be Lil Hal's fondness of harsh language contrasted with Equius's aversion to it, which causes his speech to involuntarily "glitch" whenever he uses profanity, effectively censoring himself.
Additionally, Lil Hal displayed a preference for typing in red, yet Equius hates (or at least used to hate) colors low on the Hemospectrum, with red being the lowest. This does not appear to be an issue, though: Arquiusprite seems to enjoy the color.
Arquiusprite was prototyped with Equius's body by Gamzee, and then with Lil Hal. After he is prototyped, he talks to Dirk, and he later convinces Dirk to become a trickster alongside Roxy, Jake, and Jane. Soon after Dirk gives in, Arquiusprite becomes painfully depressed by his Equius half who is reminded by the sight of Fefetasprite that Nepeta Leijon, his moirail, was killed and he was unable to protect her as he had sworn to do. Arquiusprite begs Dirk to help him overcome the emotional trauma but Dirk refuses, bitter about having been pressured into becoming a trickster.
Arquiusprite attempts to communicate purely with the Nepeta half of Fefetasprite, causing her unrest, leading Erisolsprite to attempt to help her Feferi half, telling her to ignore Arquiusprite. The conflict causes Fefetasprite to (dear, sweet, precious) Fefetasplode, bringing Arquiusprite even more guilt. Later, once the Prospitian ship crosses the Yellow Yard into the B2 session, Arquiusprite and Erisolsprite meet up with the B1 sprites on LOTAK.
Arquiusprite especially values the meeting with Davesprite, with Dave being the pre-scratch version of Dirk's brother/ancestor. He later realizes their connection is even deeper, with them both being supposed "copies" of their respective corresponding players.
In the new timeline created by John's retcons, Arquiusprite still exists, but he was prototyped by Vriska instead of by Gamzee. Some time after his prototyping, he is seen on the victory platform, in the process of disabling Jane's Crockercorp Unreal Thoughtwave Tiaratop while she is asleep, which he quickly succeeds in doing. Immediately afterwards, he deems his work for the party done, and leaves for places unknown.
In Act 6 Act 6 Act 5, Arquiusprite aids Dirk in Caliborn's Masterpiece by grabbing Caliborn, giving Dirk time to try to destroy Caliborn's soul and suck him into Lil Cal. Unfortunately, this involves Arquiusprite also being sucked into Lil Cal, which ultimately makes him part of Doc Scratch and LrdEnglish.
Arquiusprite is the only B2 sprite not to be made from the remains of two trolls.
If one compares Equius' sign with Arquiusprite, one can notice the former evokes a rudimentary bow as used in ancient times while the latter evokes the modern bows used by modern commandos and military, making a parallel to the evolution of both Equius and Lil Hal.
In addition to him and Davesprite both being prototyped from alternate versions of a Strider, Arquiusprite was first prototyped with Equius, a troll associated with horses, while Davesprite had at first been prototyped by the Rambunctious Crow. Just as Dave is associated with crows, Dirk is associated with horses.
His sweat is orange, and so are the cracks on his glasses.
Much of his conversation with Dirk descends into this:
If one pronounces his name "Arcuius", one can notice that Arc means bow in French, mirroring Equius's love of bows.
Similarly, Arquus in Latin translates to bow, which is only one letter off from Arquius.
Unless you count AR's original text color, (In which case, the two halves being Blue and Orange, which are complementary) Arquiusprite is the only B2 sprite where the two prototypes don't have opposite colors.