David, Peter. Vendetta. New York: Pocket, 1991.
A big sibling of "The Doomsday Machine" of the original Star Trek (q.v. under Drama) turns up and turns out to be a device to fight the Borg. The new machine is "a somewhat sentient ship" containing "the souls of the dead alien race" that invented it; their "mindless determination to destroy the Borg make them just as dangerous to the United Federation of Planets as the Borg." Rev. Daryl F. Mallett, SFRA Newsletter #190 (June 1991): 67-68, source for this entry, and quote.