Having a sentinel with the power [Durability] from the Invulnerability set makes it so that Blarf cannot defeat the sentinel. Hence no badge is awarded. Using [Disable all powers] I was able to bypass Durability and get the badge. GMs Globetrotter and Ghost Widow were witnesses. At their request, I also switch builds but did not train up the new build, hence no powers, and Blarf was able to defeat me, also.