connection between this movie and the second one?

I only saw the second movie. What is in the first movie? Does the first movie fill in the gaps in the 2nd movie and vice versa?

The 2nd movie begins with the backstory of the Black priest's parents as well as White Priest's story as a child. And then the film jumps abruptly to like years later when Gordon Liu plays White. (The character was played by 2 other actors earlier in the 2nd movie)

So is the first movie take place in the "gap"?

thanks