Xyrex is a powerful warrior in his and Luke's timeline,he's known as a legendary warrior in their timeline,he's not a saiyan like Luke or any of the others,he's one of the only few humans in the timeline,he doesn't turn super saiyan or any of the other forms,but he can take down any enemies that are god level,his sword is the key to his victories.  Its kind of hard to believe, but Xyrex was Luke's teacher back in the day when he was still training,Luke's father,a god of destruction hired a trainer for him since he was busy half of the time,the two didn't get along well,until Xyrex realized the potential within him when they battled,before Luke,Xyrex was the second strongest fighter in the entire timeline besides the god of destruction, the two eventually got close over the time during training,now they were close friends,of course,now a days,the two still train since Xyrex could become stronger as well. Xyrex still has kind of an attitude towards people he doesn't know,so be careful.