In Dragon Ball Z he is a badass Saiyan that is spoken of in legends. He was born on the same day as kakarot (Goku) and hates more than anyone can hate anything because goku was bawling for hours shortly after being born. When Broly was born he had an insane power level of 10,000 which freaked out King Vegeta so he had the baby killed along with his father Paragus. Later on he met Goku again and sparked up pure rage unleashing the legendary Super Saiyan. This freaked out Vegeta(King Vegeta's son) and refused to fight him until later on. Only using all of goku, piccolo(a green alien from planet Namek), trunks(vegeta's son) and gohan (Goku's son) were they able to defeat him but he later found out he lived in another movie and got blasted into the sun, and also had a clone later on in another movie.
When a man overly criticizes a women who is clearly attractive, man must post pictures of current girlfriend for comparison. In the event that man has an ugly girlfriend or none at all, man must GTFO.
The ultimate source of bro truths and man wisdom. They are usually the last stopping ground before making major bro decisions, such as what fantasy player to draft first or what to do when your new girlfriend has a freak out for the first time. Multiple Broly Grails can exist, but are few and far between, and will naturally default into a general hierarchy, such as the Jedi.
Ask Dan for advice about the three girls you're dating, after years of crazy relationships, he's the Broly Grail for this type of thing.