What is a Rescuer? - Choir Devo

I am always looking for new music and love when Rend Collective puts it out so we can do it too.  (Check out their new album Yahweh it's got some new styles mixed in with their previous genre).
I got an email this week - the other music teacher had sent me an acoustic version.  If you don't know the song take time to listen to both versions. 

Now, what is a Rescuer?