A Brommando is a tactical unit of Bros or an individual Bro that helps other Bros out when they're in a situation that is turning into a total Brotastrophy.
Brommandoes are simply dedicated Bros that is always there for you when it gets complicated.
"Yo dude, only the Brommando can fix this party"
"The Brommando saved the party from turning into a bropocalypse"
"The Brommando must've entered the TESTOSTERZONE or something because he made everyone so PSYCHED!"