http://www.ew.com/article/2016/10/28/sp ... list-arrowShowrunner Marc Guggenheim:
“Dolph brings so much presence,” Guggenheim says. “He really holds the screen incredibly well. It’s an enormous amount of fun to see him and Stephen [Amell] in scenes together.” As for the character, Guggenheim says, “Kovar is very much a villain certainly in the Arrow vein, which is to say he’s pretty badass, he’s pretty evil, but he, of course, does not think of himself as such. He thinks of himself as doing the right thing, which, in that sense, makes him very similar to a lot of the villains that we’ve had in the past. What is interesting about Kovar is he has a mix of intelligence and physical presence that we haven’t necessarily seen. He’s physically bigger than a lot of our villains that we’ve had in the past.”
Not being "in", feeling "too old for this" or simply not following the show makes it sound kinda dull the way the storylines/subplots are presented by websites:
https://www.cinemablend.com/television/ ... w-villainsKovar was first mentioned back in Season 4 when Oliver's flashback friend Taiana revealed that he was menacing her village back in Russia. Oliver promised that he would free her village from Kovar's rule, and he's spent most of his time in the Season 5 flashbacks building the skills it would take to kill Kovar. His old Bratva buddy Anatoly warned Oliver that the only way that he could possibly defeat Kovar is with the backing of the Russian mob, so it makes sense that Kovar would be imposing both with his intelligence and his ginormous size.