The Antithesis, originally 'Antithesis to Succession Itself'(note the lack of a 'the') is the primary enemy of the Nonpareil. It is separated into portions, of which only the one led by Viera had any relevance with the storyline of RP:PSAT.
Viera had three deputies to take charge of his forces at times, as well as two tan Pikachu, who were associated with the forces as a [REDACTED] and whose purpose was to [REDACTED]. One was a spy within the Nonpareil until a hundred years prior to RP:TFI. After the betrayal of Vahashii, Viera's forces were considered the last [REDACTED]. For the most part, Viera's group [REDACTED], but retained the appearance of being the extent of the Antithesis.
Etymology
The word 'antithesis' is a synonym of 'opposite.' It comes from the Greek 'antitithenai,' 'set against.'