Mmm... I cant say I know a lot but I do know...

Their original job, just like the other orders, they were supposed to simply protect pilgrims to the holy land but then they were like "Screw this we want a castle!" and by "a castle" I mean a lot of castles.

Not all of the Knights were actual knights, but a lot of them were also monks as well as Cooks, squires and stable masters similar to what you would see in todays modern military

They were mostly a mix of Germans (Prussians) and Poles

They were catholic and their patron was St Mary

Thats off the top off my head and probably nothing you could t find on the internet