Arachne is a minion of the game's primary antagonist, Garn, though she ends up betraying him early on to fulfill her own ambitions. The villainess encourages and brainwashes the other insect leaders into attacking humans, and also has the protagonist's mentor, Wynn, under her service. What she does not realize, however, is that Garn has known about her plans from the start, and that he is, in fact, the one who truly has Wynn under his control.
At the caves, Arachne severely wounds another defected minion of Garn's, Leea , and then engages Raidy in battle. Losing the first round, she then reveals her true form: that of a half-woman, half-spider. Losing a second time, she commands Wynn to finish Raidy off, but the man - under Garn's direction - murders her instead.
Unlike every other female boss in the game, no "punishment" scene takes place following her defeat.