Factoids that are (probably) no longer applicable to canon!
His living name was once Jonathan Lane.
It was said that Arackniss hates BOTH of his siblings, though the reasons are currently unknown. In old art, it was implied he hated Angel due to his brother bullying him as they grew up.
He was once responsible for Angel's death, giving him a black eye and killing him.
His own death followed seconds after Angel's; He was crushed by a shipping crate
It was once noted that while Angel was not venomous, Arackniss was.
Arackniss was not given a headcanon voice by Viv publicly, at the time stating it would be pointless since he doesn't talk much.
Previous art of him as a human depicted him as being shorter than Angel in life, as well.
Arackniss has never been depicted truly interacting with any of his other family members, though it's been stated he hates Molly as well.
He was stated to "hate how things are now" after his death.
In a stream, Viv has claimed that Arackniss is the only member of his family without a drug related name... Which she finds hilarious.
Viv has also said in a stream that Arackniss "Sucks", but she's excited for him because she likes characters that suck.
Originally, he was part of the Hotel Guests, even appearing in the banner for group's ask blog and a few group sketches. He was removed eventually, for unknown reasons.