FTX cofounder Gary Wang is set to testify against his childhood friend Sam Bankman-Fried. Here's what we know.

• FTX cofounder Gary Wang was a critical player during the rise and fall of SBF's crypto empire.
• Wang also served as FTX's former chief technology officer but kept a low profile.
• Wang has been cooperating with prosecutors and is set to testify in Sam Bankman-Fried's trial. 

Gary Wang, the cofounder of FTX, has been a mysterious but critical player in the rise and spectacular fall of the crypto empire.