IPC

How did they track them? IPC really have people everywhere in the galaxy, but what really brought Ruby there was Johan, accidentally. He was spotted on Earth and then followed back to Nortrig by Ruby. He is a mercenary from the IPC, one of the best in the field and a follower of the Path of the Hunt. He has been after Johan in particular for long. His element is fire.

As Ruby studied Guyun, he also spotted Kafka and Blade, finding it the perfect chance to bring all of them to justice but how to catch three birds with one stone? He knows very well their reputation and what a difficult task that is.
He is still playing around with them, studying their reactions and figuring out if they have some common business in there. He knows where Johan lives already, but willingly didn't touch the place.

He plans something different for each of them. He wants to kill Kafka, as there are no other options to control her. Tie Blade, make sure he means no threat anymore. And Johan, who has a special place in his heart, he wants to torture him.