Six main Avengers, a handful
of S.H.I.E.L.D mainstays and three flesh - and - blood newbies, not to mention a
robot army, means it's
already a battle for screen time, yet AOU still manages to be cameo - tastic, bringing back a host
of favourites from previous stand - alone movies as well as some significant fresh supporting characters (including Andy Serkis as an arms dealer who's afraid
of cuttlefish).