I am very happy after 5 months of grinding I was able to beat the final boss in the black sun, red sand arc
. He was difficult, but I went ar, sword and I kept at a distance.
A few things before anyone takes him on get ql9 4 blue and the rest can be green. For the weapons if you go ar or any other ranged try and get max ql10 and if you get it in blue. Then when you die three times (there is nothing stopping the three deaths) I went with heal, defense, and pen, attack rate. Also when get gets say 3k worth of xp move up to him and use your melee attacks or your hardest hitting attacks to win.