A Scout Marine is an aspirant of the Space Marines who has received the majority of his gene-seed implants but has not yet earned his full battle-plate or the sacred Black Carapace. Organised into the Tenth Company under the codex doctrines, Scouts serve a probationary period in which they prove their worth through reconnaissance, infiltration, and the patient arts of the hunt.
Clad in lighter carapace armour rather than full power armour, Scout Marines rely upon stealth, marksmanship, and cunning rather than brute resilience. They range ahead of the main force, mapping enemy positions, sabotaging supply lines, and striking from ambush before melting back into the shadows. Through such trials a young warrior learns patience and self-reliance before he is entrusted with the full might of the Astartes.
Upon completing his training and receiving the final implant, a Scout ascends to the rank of Battle-Brother and takes his place among the line companies, his years in the shadows having forged the instincts that will serve him across a century of war.