Arcturia was a female half-fey human worm that walks and one of Halaster Blackcloak's apprentices, who were collectively known as the Seven. She resided in Arcturiadoom, deep in Undermountain.[1]


Through much magical experimentation, Arcturia had transformed her human appearance into that of a half-fey, with sylph-like wings and fine scales of blue to protect her body.[3] However, after her death during Halaster's Higharvestide, she was once more transformed through her carefully prepared contingency magic into a worm that walks. Her true form became one of a vile undead amalgamation of worms, though she would wear a mask to hide her inner appearance.[1]


Much like Muiral, Arcturia's madness led her to experiment with bodies, both hers and others. Perhaps Halaster's most ambitious apprentice, she was known for her cruel experiments with polymorphing others to suit her whims.[3]

Since Arcturia's death and transformation into a worm that walks, she became far more measured in her activities and began to carefully plan and place contingencies for all eventualities.[1]


In 168 DR,[5] Arcturia arrived with Halaster Blackcloak and the other members of the Seven at Mount Waterdeep, where they constructed Halaster's Hold. She dwelt here for many years, studying and residing in one of the many lesser towers that ringed Halaster's.[2]

As Halaster spent more time in Undermountain instead of his tower, he eventually lured Arcturia and the other apprentices into the dungeon where they were tested by Halaster's creations. By 307 DR, Arcturia had broken ties with Halaster and established a domain of her own in Arturiadoom.[5]

On the morning of Highharvestide, in 1369 DR, Arcturia was slain by four frost giants after members of the Twisted Rune captured Halaster and sent the magic of Undermountain awry.[4] Despite her death, she still managed to kill two of the giants and was able to activate her contingency magics to remove her corpse and left an illusion of her dead body instead.[4][1]

After her body was returned to her sanctuary, she rose as an undead creature known as a worm that walks.[4][1]