The Apothecary advances as a Savant, and nothing else. Its whole Primary access goes to the craft of the field surgeon — the mind that keeps the wings on their feet when the shooting will not stop. Secondary opens wider: Ferocity, Leadership, Shooting, the Chapter's Signature skills. From there the gene-warden can grow toward a steadier hand in the fighting, or a firmer voice behind the line.
The Captain advances as a fighting commander. Its Primary access runs to Combat, Leadership and the Chapter's own Signature skills — the master swordsman who also bends the whole strike force to his will and its two wings to their postures. Its Secondary reach is broad, taking in Agility, Brawn, Ferocity, Savant and Shooting, so no path of advancement is truly closed to the officer the host forms around.
The Centurion is a walking weapons-platform. Its Primary access sits on Brawn and Shooting — the strength to bear the warsuit, the gunnery to make it count. Combat, Ferocity and the Chapter's Signature skills wait at Secondary. Close-quarters bite, for a fighter built to plant itself and fire and not give the ground back.
Zeal and command. The Chaplain's Primary access falls on Ferocity and Leadership — the warrior-priest who drives the line forward and will not let it break. Its Secondary reach takes in Brawn, Combat, Shooting and the Chapter's Signature skills. From there the crozius-bearer leans into raw fighting power, or into the darker offices the Chaplaincy alone is permitted to keep.
The Deathwing Terminator advances as the anvil it is, its Primary access unusually broad for a line fighter — Brawn, Combat, Shooting and the Chapter's Signature skills all open, the veteran who can hold, hammer and endure at once. Its Secondary reach is the single set of Ferocity, sharpening the aggression the anvil keeps in reserve behind its patience.
The Dreadnought advances slowly, and narrowly. Its Primary access is a single set — Brawn, the raw power of the interred hero's chassis. Combat, Ferocity and Shooting open at Secondary, sharpening the ancient walker into a deadlier engine. The brother within changes little across the years. The machine around him learns to kill better.
The Librarian advances as a Savant above all — the disciplined transhuman mind — and its Primary access carries the Interromancy discipline it manifests, drawn free at creation. Its Secondary reach spreads to Cunning, Ferocity, Leadership, Shooting and the Chapter's Signature skills, and to the universal witch-blast of Smite, so the psyker can grow toward the sword, the command role, or the deeper mysteries the Inner Circle keeps.
The Lieutenant is the Captain's second. Its Primary leans to Leadership and the Chapter's Signature skills — the officer who carries the plan to the part of the line that is failing. Secondary runs almost as wide as its master's: Agility, Brawn, Combat, Ferocity, Savant, Shooting. Whatever the strike force is short of, the Lieutenant grows toward it.
The Marine is the disciplined heart of the line. Its Primary access runs to Shooting and the Chapter's Signature skills — steady gunnery, and the doctrines that bind a strike force together when nothing else will. Brawn, Combat and Ferocity open at Secondary. So a battle-brother can grow toward the melee, or toward the fury the wings draw on, and still be the backbone the rest of them form up around.
A hunter on wheels. The Mounted Marine's Primary access is Agility, Cunning and Shooting — speed, guile, and guns that do their work in passing. Combat, Savant and the Chapter's Signature skills open at Secondary. The rider grows toward the melee, toward sharper judgement, or toward the disciplines that hold the Ravenwing together at the gallop.
The Ravenwing Black Knight advances as the head of the hawk, with wide Primary access — Agility, Combat, Cunning, Shooting and the Chapter's Signature skills all open, the master rider who strikes, deceives and outruns the answer. Its Secondary reach takes in Brawn and Ferocity, adding weight and fury to a fighter otherwise built for speed.
The Scout is the strike force's forward eyes. Its Primary access sits on Agility and Cunning — the neophyte who moves unseen and seizes the ground ahead of the line. Savant, Shooting and the Chapter's Signature skills open at Secondary. This is the first stretch of a long path. Survive it, and a Scout is carried up into the wings.
An artificer with a fighter's strength. The Techmarine's Primary access is Brawn and Savant — the craft of the Machine Spirit married to the power to close a fist and break a skull. Combat, Shooting and the Chapter's Signature skills wait at Secondary. From there the artificer bends toward close work, toward marksmanship, or toward the disciplines that bind the two wings as one.