"like a Judas, an Ephialtes"

Judas Iscariot was a follower of Jesus who betrayed him to the Roman authorities, and thus was instrumental in bringing about Jesus' execution. 

Ephialtes was a Greek soldier who betrayed the Greek army at the battle with the Persians at Thermopylae.  This battle is the subject of the 1998 comic and 2007 film 300.