The only apparent reference to Orcneas in known recorded Anglo-Saxon history comes from the tale of Beowulf 1.111-4 when referring to Grendel’s dwelling place:
“From there all monsters arose –
Ettins and elves and orcneas
Likewise the giants who strove against god
For a long time – he gave them their reward”
Grendel from Beowulf was deemed to be aquatic or semi-aquatic “fifel” (Perilous/Mighty supernatural being) given that he made his home amongst the fens and swamplands. Fifeldor (Mighty Doorway) was the description given to a mighty river that formed the southern boundary of Anglian territory in the story of Offa of Angeln, named as Egeduru (Which became “Egidora” or Doorway of Fear) and is now known as the River Eider.
The word “orcneas” has been debated in terms of its meaning and the type of fifelas (monsters) it refers to. It has variously been tied to “orca” as in “sea monster” or “whale” as this may tie in with the aquatic dwelling of Grendel except for the –neas ending which defies explanation in this context. Bosworth-Toller suggests that it is derived from orcen “possibly(!) meaning a sea monster”.
Another examination determines that the name derives from “orcus” meaning “underworld” and “-neas” meaning “corpses” thus suggesting that orcneas are in fact the animated dead, returned from the underworld.
Popular fantasy has painted orcneas or “orcs/orks” as brutish, variously green or grey-skinned and even potentially a distant cousin of ielfe, long since fallen from grace and twisted by evil. They are also referred to as goblins by Tolkien, just to add to the confusion.
The link is there in Beowulf for all to see, and it is perhaps understandable that one explanation has been that orcneas and ielfe are two sides of the same coin. Given that both were described as beings that Grendel lived amongst, alongside the ettins and the giants, the physical appearance of orcneas in direct comparison is harder to tie down from a factual perspective.
It is often postulated that ielfe are linked to barrows or burial mounds and it could well be that they are linked to orcneas in the form of the animated dead, perhaps particularly those who met their end amongst the fens and swamps of old England, or following skulduggery and evil actions. Evil begets evil, after all.
Suffice to say, such beings have long been associated with malevolence, fear, foreboding and ill intent. The dead coming back to life to take revenge on the living, or to right a wrong forms part of folklore going back centuries and as such, orcneas are something to be incredibly wary of, lest you meet a similar fate.