The R-Vanguard is the name for the main cast in R5 Central. It's comprised of:

Mike

Main host and producer of the show. Also main pilot of DaiRaiGou

Ai

Co-Host, on-board A.I. for RaiDecker and occasional DaiRaiGou co-pilot.

Sylene

Co-Host, also occasional DaiRaiGou pilot

Mai

Co-Host, team maid mascot