Anyone else hate this kind of thing?

Once you reach that one point of the tower, Doga just goes and basically kidnapps various charicters. He dosn't actually tell them what's going on, they just sort of go along with a compleate stranger because he mentions a friend.
Without knowledge of the imediate situation the proper reaction to that kind of thing should be something along the lines of "What the **** are you talking about?", or who the **** are you?"

And yet at that one point it was screaming ulterior motive. Of course when you get down to the bottom of everything, you know the type of person they are. Do the NPCs know that?

He tells them to come, its an urgent situation so they are like commanded to follow. I know you would do the same. ~Mettaur_15 owns me

Maybe Doga had something that belonged to the 4 main characters and he showed them to the guest characters, but it's not shown in the cutscenes.

You can assume anything on this, really...

If there's another conspiracy theory, I'd love to hear it.

ok that's crazy i havn't seen doga but they must have had an instinct in them telling them to go.

Maybe they follow him because they know their friends are out on a life-threating quest to save the world. If i knew my friend would be doing something very dangerous, and then some random comes forth saying:
"oh god, <insert name> is in danger, you have to help him!"
i would definitely come.