Karl Iscove

"A bow and arrow's not his usual M.O."

- Felicity Smoak about Karl Iscove

Karl Iscove was a paid assassin hired to kill Owen Post.

Biography
At some point in 2017 Iscove was hired to kill Owen Post specifically with a bow and arrow.

Not long after that Iscove was assasinated himself, presumably also by Diaz. The captured footage of Iscove killing Post was then doctored to look like Oliver Queen did it.

Abilities

 * Trained assassin: Iscove was a known assassin who had enough skills to use them for living.
 * Skilled archer: Iscove had at least rudimentary skills in archery as he was able to assassinate Owen Post with certain precision from a distance.

Former equipment

 * Bow and arrow: Although not a part of his usual modus operandi, Iscove used them to assassinate Owen Post.

Triva

 * Although it was implied that Ricardo Diaz had Iscove killed, the fact that Oliver Queen was well-aware of Iscove and his current status might be a sign that he was somehow crossed paths with Team Arrow previously.

Behind the scenes

 * Surname Iscove is a very likely reference to Robert Iscove, American veteran television director who has directed the pilot for 1990's The Flash starring John Wesley Shipp, Amanda Pays and Alex Désert. Creative team of Arrow also did their own version with numerous references to 1990's version, but it should be noted that inspiration was also evident in the first season of Arrow.
 * It should also be noted that The Flash makes a brief cameo in the same episode as Iscove's first full appearance.