The names given (by themselves, so nobody else can be held to blame) to the three Giantish triplets, once they've been possessed by the Ravers. These terror-inspiring outsized abominations against nature appear in The First Chronicles of Thomas Covenant.
Long, long ago, well before a certain gaunt and grumpy leper's first visit to the Land, High Lord Damelon woke up one day feeling all prophetic. So he summoned the Unhomed - the name given by the Landish inhabitants to The Giants of Coercri who had broken their nautical sat-nav and thus couldn't find their way home - and told them of his visionary dream. His mistily perceived augury stated that, once the Giants' seed regained its vitality, the BFGs' long search for their home would soon be at an end.
Now nobody quite knows what the Giants did to attempt to revitalize their seed - and that's quite possibly a good thing, or else one might be beset by disturbing imagining. One rumour has it that a number of seedy night-clubs sprang up almost instantly in the backstreets of Coercri, in which Swordmainnir twirled themselves enthusiastically yet ungracefully round specially reinforced poles on stage. One would have to be brave indeed to patronize such establishments, since if you were unfortunate enough to have a pair of granite Giantish panties tossed into your face, you'd lose consciousness and a fair few teeth simultaneously. Another theory states that Coercri lacked those femme fatale warriors (which eventually lead to the self-despising depression and the demise of the population) and that they indeed had to devise means best left to Giantfangirlish imagination and the realms of fanfiction.
Be that as it may, by the time of the First Chronicles, whether by luck or by effort, Wavenhair Haleall, wife to Sparlimb Keelsetter had given birth to bouncing baby Giantish triplets, all of them boys. One hates to think of both a) the diaper bill (Giant babies have prodigious appetites) and b) how absorbent granite diapers actually are in the first place, but that's all beside the point. Saltheart Foamfollower is despatched to Revelstone to tell the Council of Lords the good news and also to source some magical outboard motors made of gildenlode, a puissant wood, to help the large lost ones on their way home, as is related in Lord Foul's Bane.
Unfortunately, forty years later as described in The Illearth War, it transpires that all three brothers, now all grown up, have become possessed by the Ravers at Lord Foul's bidding. Such a thing would not normally have been possible, were it not for the added malevolent influence of the Illearth Stone, since giants are normally too strong-willed to be coerced by any unclean spirit. This puts a definite crimp in the giants' day.
Deeds in the First Chronicles
The first giant-raver, naming himself Kinslaughterer - though more normally known as turiya Herem - does exactly what it says on his tin and promptly slaughters all his kin, i.e. all the giants within Coercri - which in fact comprise all the giants within the Land as a whole at that time, with the exception of Foamy, who has decided to take up guerrilla warfare. This task is made all the more easy for him, because the BFGs are so unnerved at what has happened that they just sit around in the deepest depression at home like so many oversized emos, waiting to get slain. Thus Damelon's prediction becomes true, although not in any way that anyone had expected - damn tricksy things, these prophecies. Anyhow, Kinslaughterer is himself killed - though not the raver possessing him - when he's bitchslapped upside the head simultaneously by Korik, Sill and Doar, Bloodguard and haruchai.
The second overly large and evil brother, now calling himself Fleshharrower - though again more normally known as moksha Jehannum - takes command of Lord Foul's vast armies of evil creatures and advances on Revelstone. If his brother is anything to go by, presumably Fleshharrower really enjoys harrowing flesh. Anyhow, as general-in-chief of the Forces of Evil™, he decimates the Lords' army, led by Hile Troy and almost wiping out The Good Guys™ entirely, until getting overenthusiastic and enticed into the fell forest of Garroting Deep, the demesne of Caerroil Wildwood, the grumpiest and most psychopathic of all the Forestals. It is then that Hile Troy makes his desperate bargain with the Forestal and the day is thus saved at the very last minute. Ain't that just like a fantasy novel... just when you think all is lost, Good prevails. Anyhow, Fleshharrower is gleefully garroted by Wildwood at the end of The Illearth War, swinging on the gibbet at Gallows Howe like some outsized horror show piñata - which of course doesn't kill the Raver within him, but certainly gives the Forestal some jollies.
The third member of the gruesome threesome - entitling himself Satansfist for some reason (it's best not to think of what Satan might do with his fist, but it may explain why Lord Foul considers samadhi Sheol his right-hand man) - doesn't make an appearance until The Power That Preserves, the final book of the First Chronicles. Set a further seven years on, it details how Satansfist has taken over as commander-in-chief of the rebuilt Forces of Evil™ and is laying final siege to Revelstone. Not to worry, though - this is a fantasy novel after all. Sure enough, after a much protracted battle, Lord Mhoram finally stops being a bleeding-heart vegan namby-pamby liberal and with his new-found righteous fury is able to dispatch the corporeal form of the last Giant-Raver by busting a cap in his Giantish ass (well, okay, by shish-kebabbing him with Loric's krill, if you must know).