what are they fighting about?????

The blonde one wants revenge for being left behind to die so he's working for the other guy which I guess he's collecting people with ki for his experiments or something it seems unclear as of the bigger purpose.

The scientist and Scorpion (the blonde guy) are trying to wipe out the Murim people. Scorpion is mad that the main family tried to kill him because he killed someone. But their goal is more to collect all the ki the Murim people have and create an army of robots to gain even more power.