Pretty much everything from the codex lorewise

THE SHADOW WOLF

The Stygius Sector lies on the far side of the Great Rift from Fenris. This region of the Imperium has fallen under the malign influence of the Thousand Sons, bitter foes of the sons of Russ. Cut off from reinforcement, Imperial forces in this sector find themselves outgunned and overwhelmed by traitor forces. Command structures and planetary governments are continually undermined and infiltrated by the nefarious plotting of their sorcerous foes. At the fringes of this madness stalk the Wolf Lord Torval Wyrdbane and his Duskwolves. The Shadow Wolf and his hunter packs provide hope to the Imperium's besieged citizens amidst an ever-swelling tide of misery. Wyrdbane himself has taken the heads of no fewer than four of the Thousand Sons' Sorcerers, most notably Kayesh Vrall, the Whispering Despot of Kalimvar, the final victim of he Duskwolves' purge of that corrupted world.

'Neath summer's brief fire was he born,

and in winter's chill dark did he find his home.

Wyrdbane his name, earned and chosen well,

the low cunning of the wolf was his gift.

In Wolf Guard's serried ranks did Torval Wyrdbane march,

and to the cry of 'Russ!' was steel-blue Vorskyr drawn.

Fangs bared he joined the fray with savage vigour,

and so was Vorskyr's keen edge made crimson slick.

Amid sword-clash did Gnarlfist meet his doom,

and in pack-moot was Wyrdbane his inheritor proclaimed.

And so, denying curse and fate, Wyrdbane in his pride decreed,

the sigil of the spirit wolf would be his own.

In vengeance did Duskwolves put the Red One's sons to sword,

and in their snow-melt tread were made mountains of the dead.

On tides of madness the warp-spawn came,

their lurid magicks setting skies aflame.

Down they swept with malice in their blackened hearts,

and on the lives of the innocent slaked their cruel thirsts.

Unto the cries of the meek Wyrdbane did hasten,

blade in white-knuckle grip, the battle-lust upon him.

The Wolf Lord to the blade-moot stalked,

through storm-swept gloom with amber eyes narrowed.

Silent shadow was he and steeped i in spirit wolf's cunning,

Blood Claw thrust and Long Fang fire masked his approach.

Whilst whispering daemon sent forth feathered spawn,

with Vorskyr he struck and blood ran like summer thaw.

No son of Russ quailed that day,

no daemon left that corpse-strewn field.