Can someone give me a general understanding of "Osiris"?

[Ishinan]

The following text comes from _Gods and Myths of Ancient Egypt_ by
Robert A. Armour:

Osiris, God of the Underworld, was always dressed in white mummy's
clothes; he wore a beard and held in his crossed arms the crook, the
flail (whip), and sometimes the scepter - all signs of authority and
power. Most often he was depicted as the judge of the dead person's
soul. He was shown standing on the platform throne of Maat (depicted as
a shallow rectangle) or seated upon a throne floating on water out of
which sprouted lotus flowers. On his head Osiris wore either the white
crown of Lower Egypt or the atef crown, which was a combination of the
white crown and two white plumes. The color of his skin helps to
identify his qualities: sometimes it was painted white like a mummy,
sometimes black to suggest death, and at times green to symbolize
vegetation and resurrection.

Some scholars believe that Osiris may have been an actual human ruler
early in civilization, but it is fairly certain that in prehistoric
times Osiris became a minor fertility god associated with Anedjti, the
chief god of the Delta village of Busiris. From Anedjti he took the
crook and flail as symbols of power. In this form he apparently had the
character of a dangerous god, and some suggestions of this trait (the
crook and flail, for example) survived into later times.

Sometime before the historic period began and Lower and Upper Egypt were
united into one country, his image was transformed into that of a kind
ruler who acted as guide to the underworld. His fame spread from the
Delta into Upper Egypt and eventually Abydos became the center of his
worship, although he was respected and worshipped throughout the
country.

According to the myths, Osiris had become very successful as a ruler and
leader on earth, teaching human beings to give up barbaric practices and
to learn to grow grain. His brother Seth grew jealous and killed him by
sealing his body in a casket and throwing it into the Nile. Isis,
Osiris' wife and sister, sought the body of her husband, but even after
she found it, Seth continued to plague her. This time he cut the body
into pieces and threw each piece into the River Nile. Isis faithfully
began the long search for the pieces. When she found them, Thoth and
Anubis wrapped them in mummy's clothes and restored his shape; Osiris
then became the god of the Underworld.

In the meantime, Horus, the son of Osiris and Isis, had grown to
maturity and swore to seek revenge for his father's death and
mutilation. He sought out Seth and they fought the epic battle of
Egyptian mythology. Horus eventually won and the rest of the gods made
peace.

As god of the underworld, Osiris became respected above all other
Egyptian gods. He was responsible for receiving reports from other gods
of the recently dead person's soul as it progressed through the trials
of the underworld, and for rendering final judgment on the fate of the
soul. He was usually attended by Isis and Nephthys and assisted by
Thoth and Horus, who spent only part of their time in the underworld,
having earthly responsibilities as well. The jackal-headed god Anubis
was responsible for embalming and generally preparing the body and, as
such, was Osiris's chief assistant.

Most of what we know about Osiris comes in textual form. The Pyramid
Texts, the Coffin Texts, and the Book of the Dead* contain the basis of
our knowledge about Osiris' role in the treatment of the dead. The Book
of the Dead's vignettes provide us with drawings of the god that are
especially vivid (and are often reproduced in the tombs of the dead).

* For more information regarding the Book of the Dead, you might want to
check out the following website:

http://www.lysator.liu.se/~drokk/BoD/

Hope this helps and leads you even further into Egyptian Mythology - a
fascinating trip.