Type 2 - The Wulfenkind 

The second, though hardly less redolent type of Wulfen, is the 'lost comrade'. This type is not strictly perceived as balefully as the first type of Wulfen, though their 'wyrd' is a complex one in the Space Wolves' eyes.

A common element between the second and first type are the aspects of loss and bodily transformation. The 13th Great Company are the Wulfen-Kind, and were lost to the Chapter 'whilst pursuing the Thousand Sons', their old enemies. Since then, there have only been 12 Great Companies within the Chapter as a formation. (Kelly, pg. 9) [1] In their chase of the Thousand Sons, the 13th were 'lost in the Eye of Terror for ten millennia'. (Chambers, pg. 18) [2] This basic story, though elements have shifted and changed over time according to the narrative choices being made, remains mostly consistent. What has changed, however, are specific details and the extent to which they are 'true' in the paratext.

For one thing, in 2003's campaign book entitled Codex: Eye of Terror, the bestial Wulfen are at best a tertiary element of the Great Company, though all members 'bear the curse' (Chambers, pg. 34). Dedicated, bestial Wulfen exist to some extent, and their tactical use is remarked upon as a sign of the wider desperation experienced by the brothers. Much of the war-graith of the 13th is scavenged from dead Heretic Astartes. This is emblematic of loss, not just of self, but of a wider group identity. Indeed, 'Imperial observers believe the 13th Company has split into a number of smaller warbands, each forming the retinue of an individual Lord'. (Chambers, pg. 35) In the wake of Prospero, of the loss of Russ, of their loss of direction, the 13th are aimless, going from place to place, fighting seemingly for the sake of causing their enemies pain. 

Yet the Curse of Wulfen takes on new dimensions in these tellings. It is something to be borne with courageous dignity and patience. The Grey Slayers, the veteran troops at the heart of the lost Great Company, are 'men who served for millennia [...] and through it survived the very worst the Eye of Terror can throw at them). Whether or not the Grey Slayers and their fellows are doomed to succumb is besides the point. In the moral universe of the texts, the 13th's fight itself is noble, because it is against all odds. 

However, even this portrayal of the 13th changed around seven years later in 2016's Warzone: Fenris series of campaign books. Here, the 13th Company, now seemingly wholly consistent of bestial Wulfen, exits the Eye of Terror, and joins the Space Wolves in battling the forces of Chaos. However, not all is joyous with the recovery of these lost brothers. The Thousand Sons once again rear their head, to bring devastation to Fenris. And to make matters worse, the Wulfen themselves seem to infect their fellows with their curse. 

If we can learn anything from this type, it is the flux and tragic elements of the Wulfen. 

Footnotes
[1] Phil Kelly, et al. "Space Wolves". Nottingham: 2009.
[2] Andy Chambers et al. "Eye of Terror". Nottingham: 2003.