Borcuse and Girge are definitely the most interesting characters in this manga up to this point, and they didn't overstay their welcome. Always knew that both of them were gonna die but not in the span of 50 chapters, this author really has a unique way with pacing. Looking back on their entire arc it seems to me the author meant for these two to serve as basically foils to the MC, playing off of him to give him character development, sort of like the role Kuze played for Kiryu in Yakuza 0. Initially I thought Zess was going to be another Sasuke from start to finish but the author chose a completely different route and I much prefer it this way, again, great job by the dude.