All i get from this is that Shamura likes us more if we refuse, and questions their little brother's taste in vessels if we do (it kinda makes sense because they are the god of war, so probably like people that are ready to go to battel).
A tip how beat him use a rocket launcher kill adds fast get them group up kill them fast, use jutunn exotic kill captains and on the boss you should win If dont have jutonn use a bow