Besides Paul, were there any other enemies of the early church who converted to Christianity? As I was listening to a debate between Drs. William Lane Craig and Richard Carrier on the historicity of Jesus' resurrection, something Dr. Carrier said caught my attention. He claimed that "[Paul] is alone, actually; there's no other enemies of the church that were converted to join the church." I immediately got a hunch that this was unlikely, but I haven't had any luck in finding other antagonists to the early church who were converted. 

Based on the New Testament and contemporary (within the 1-200 AD "Early Church" period) historical records, were there any other enemies of the church, aside from Paul, who converted to Christianity? 

For reference, the debate can be found here, and the point containing the quote starts at 1:28:32. 

I would greatly appreciate citations in any answers that you might offer. 

To further clarify: I'm not looking for answers from sources that Dr. Carrier would necessarily accept as credible (although citations from extra-biblical, historical sources are definitely encouraged). To place a constraint like that on the question might make it impossible to answer, as he states in the video that he doesn't view the gospels as credible. I would certainly accept answers that reference the gospels. 

Also, for the purposes of this question, I would define an "enemy of the church" during the apostolic time period as someone who actively persecutes or opposes Jesus, the apostles, and the early Christian churches.
In Peter's sermon at Pentecost he accuses the members of his audience of delivering up Jesus to be crucified:


  "Men of Israel, hear these words: Jesus of Nazareth, a man attested
  to you by God with mighty works and wonders and signs that God did
  through him in your midst, as you yourselves know—this Jesus,
  delivered up according to the definite plan and foreknowledge of God,
  you crucified and killed by the hands of lawless men." (Acts 2:22-23,
  ESV)


Concluding remarks end on their guilt for crucifying Jesus.


  "Let all the house of Israel therefore know for certain that God has
  made him both Lord and Christ, this Jesus whom you crucified." (Acts
  2:36, ESV)


The response of the crowd was to be convicted:


  Now when they heard this they were cut to the heart, and said to
  Peter and the rest of the apostles, "Brothers, what shall we do?" And
  Peter said to them, "Repent and be baptized every one of you in the
  name of Jesus Christ for the forgiveness of your sins, and you will
  receive the gift of the Holy Spirit. For the promise is for you and
  for your children and for all who are far off, everyone whom the Lord
  our God calls to himself." And with many other words he bore witness
  and continued to exhort them, saying, "Save yourselves from this
  crooked generation." So those who received his word were baptized, and
  there were added that day about three thousand souls. (Acts 2:37-41,
  ESV)


Why would a crowd of Jews in close historical proximity to the crucifixion be cut to the heart over an accusation of crucifying Jesus, and repent and be baptized, if they were not in some way involved in the crucifixion itself? The simple answer is that they were involved in the persecution of Jesus, and therefore of early Christianity.

Whether or not this meets the definition of persecuting the early church depends on your definitions of "the early church" and "persecution."

But secondarily, what is difficult to prove in specifics is easier in statistics. Rome was not sympathetic to Christianity, and generally did persecute early Christians. And yet, the church achieved explosive growth that took the form of abandoning one's former lifestyle. Are we to believe there was zero overlap between these two groups?