The term Ganas in Hinduism is associated with God Shiva.
‘Ganas’ means a class or group. The term is generally used to refer to the
attendants of Shiva. Ganapati (Ganesha) is the leader of the Ganas. They are
described in various Hindu Scriptures – majority of them are strange and weird
looking. Some evoke fear. Some have normal looks. Some Ganas are associated
with Muruga or Kartik and they are known as Parishadas. They have faces of
animals and birds.
When Shiva in all his fury attacked the Daksha Yajna, after
the death of Goddess Sati, it was Ganas who caused the maximum damage. They had
accompanied Shiva in his marriage with Goddess Parvati. It is said that seeing
the marriage party, mother of Goddess Parvati fell unconscious and demanded
Shiva appear in a better form. To satisfy the false ego of humans, Shiva then
took the form of Kalyanasundara murti and the ganas too appeared as handsome
beings.
A detail description of Ganas can be found in the
‘Ramacharitamanas’ of Tulsidas.
Some had lean and thin bodies, while others were very stout;
some looke pure, and some impure. They wore frightful ornaments, carried skulls
in their hands, and were all smeared with fresh blood. Their faces looked like
those of donkeys and dogs, swine and jackal. Their various forms, which
included spirits, ghosts, yoginis were beyond description. (source Hinduism –
Alphabetical guide – Roshen Dalal).