A Space Marine must be fully versed in every conceivable aspect of warfare, even those he will not ultimately practice as a warrior. Thus, Scouts learn the art of subterfuge, approaching the foe unseen and striking before his presence is detected. Such tactics are rarely practiced by the Reserve and Battle Companies, as the Codex Astartes dictates a very direct form of warfare. Scouts usually perform reconnaissance missions in advance of the main force of Space Marines, gathering information, hunting down and terrorising enemy formations and relaying intelligence back to their leaders.
Every Chapter of Space Marines must recruit new warriors into its ranks in order to survive. The process varies from Chapter to Chapter, many recruiting from their own homeworlds. These are often feral worlds, breeding tough, harsh new recruits. Whatever the tradition of a particular Chapter, warriors must always be chosen when they are still young, before their bodies become too mature to accept the many bio-implants. During those years, the warrior is known as a Neophyte, or Space Marine Scout - he is neither fully a Space Marine nor entirely a normal human. A Space Marine Scout has much to learn; not only must he become accustomed to the many biologically engineered enhancements which are at work on his body, but he must learn the litany of battle that will fortify and strengthen him. He will undergo several phases of initiation into the Chapter's own secret cults, and he will get his first chance to fight in battle. Space Marine Scouts are neither as tough nor as experienced as full Space Marines. Scouts can fight alongside other Space Marines in the main battle-lines, and often do so, during moments of desperation. Once chosen from the ranks of aspirants, a human warrior must undergo the ritual trials unique to his Chapter. Once accepted, the genetic implantation and induction of the Space Marine organs begins. The warrior has taken his first steps to becoming a full fledged Space Marine. The Scout is then placed under tutelage of a sergeant who will oversee his induction and training and also lead the Scouts in battle. Not yet ready to join a company, the young Scouts live alongside their brothers in the 10th Company halls where they will sleep and train, learning the history of their Chapter. Only after a Scout has proven himself in combat will his sergeant judge him worthy of the title of Space Marine, and declare him ready to join one of the companies
Space Marine comic - conept [link]
Avisius - [link]
Ko'tan - [link]