On left:

Kynaston XI

An ambasador of Western Syntax/Syntax Crusaders. Seemingly loyal to Arcturus Mengsk, however he seems also to plot about to overthrow the emperor. Why does he serve Arcturus with great loyalty though it is unclear however his very appearence and some old memories about him might give a hint or two.

On right:

???/Neo Brainius

Initially appears as some sort of fleshy mutated muscleman who goes seemingly nude. However, he is not nude for nobody knows this is Neo Brainius, a far descendand of a terrorist who, like Neo Brainius ended up as a cyborg. Neo Brainius however was meant to be ambasador of Polar Syntax/Syntax Hermits. Why he serves Arcturus greatly unknown reason. Even more unknown reason is why he never speaks a word as he used before leaving Syntax Quantum.