Elder God (Cthulhu mythos)
The Elder Gods are immortal entities in the Cthulhu Mythos. They are generally distinguished from the Outer Gods or Great Old Ones by being less unbearable to behold (some choose to appear as humanlike figures, though their majesty is still awe-inspiring and humbling to mere mortals), and by being less generally inimical to humanity. Some Elder Gods are known to help human beings who have dabbled in the Mythos return to relative safety (though never to an untroubled psyche); it would however be a mistake to assume they are inevitably benevolent. At best, they are still vastly superior to humans and have minds and motivations beyond human understanding; their seeming friendliness may well be coincidental, or due to reasons humans cannot fathom.
The only Elder God described explicitly by Lovecraft himself was Nodens, "hoary and terrible lord of the primeval Abyss". This title implies that Lovecraft didn't consider Nodens any friend of humanity; however, later writers including the authors of the Call of Cthulhu roleplaying game have assumed him to be uninterested in attacking humans and portrayed him as occasionally aiding travelers stranded in alien dimensions to return to Earth or escape marauding monsters.
August Derleth's version of the Mythos, being inspired by Christianity and intended to reflect a belief that good can triumph over evil (sharply at odds with Lovecraft's view that the cosmos was too inherently perilous for humans to ever consider themselves safe), used the Elder Gods as his forces of good, manifest primarily through the Elder Signs which can keep the Mythos's forces at bay. It is possible that he intended Cthugha to be an Elder God, as the protagonist of "The Dweller in Darkness" summons Cthugha to dispatch a manifestation of Nyarlathotep; however it is more likely that this was due to Derleth's other controversial view of the Great Old Ones, that they were elemental creatures and could be set against each other due to their polarity. Later writers have invariably described Cthugha as a Great Old One.
Brian Lumley's Mythos writings resemble Derleth's in their use of benevolent Elder Gods; his flagship character Titus Crow makes contact with an Elder God called Kthanid and is tasked with opposing Cthulhu. Kthanid is Cthulhu's "brother" (whether in the conventional human definition or a more arcane sense) and appears exactly the same as Cthulhu save for having humanlike eyes and a benevolent persona.
Only a few other Elder Gods have been described, notably Henry Kuttner's Vorvadoss, a being who appears as a vague, nonhumanlike face behind a wall of fire, and displays a temper only barely less malevolent than that of many Great Old Ones.