Boss fight disappear? Don't worry, he'll find you again

I've been reading up on the boss fight bloopers, snafus, and confusions this morning. There's lots to read! One question that I'm seeing a lot of is "The boss disappeared when I beat him, how am I supposed to beat him 10 times, let alone a hundred times?"

The first clue to that answer is on the homepage banner. It says "Watch out for him in fights".

I just saw this in my own game - it's a banner that will appear at the top of the fight list when you are fighting that says "Limited Time Fight". Aha, so that's where he will find you. I wonder how frequently this will happen.

Further information can be found in the FAQ about this. It says the fight is activated when you start fighting. "When your activity catches the Raven's attention, the Boss Fight will trigger..."

It's safe to say this will have to be an ongoing event, if we are to beat the boss 100 times. I wonder who will be the first to finish!