When Waltz was asked what his character has against the Green Hornet(Seth Rogen), his response was "Well, because he's a competitor. There's a misunderstanding between the two of them and they have to sort it out through the course of the movie."
Here's a possible major spoiler:
"They do sort it out through the course of the movie, but unfortunately it happens fatally for one of them and it wasn't Seth."
I'm not sure if that is much of a spoiler but that thing usually happens, to villains of the piece.
-ACCESS out. Godspeed and MABUHAY