Why did Sugawara Michizane become a god?

The plum-blossom(ume) festival(梅花祭) is held at Kitano Tenmangu Shrine in Kyoto City on the anniversary of Sugawara Michizane's death, February 25th. He is enshrined in the shrine.
In fact, he died on the 25th day of the second lunar month (on March 26th in 903 according to the Julian calendar).

Political foes ousted him from power and he was relegated to Dazaifu. Shortly after He died in hopelessness, some key figures died one after another and many officials were struck by lightning while they were meeting in Imperial court. So they regarded a series of accidents as his curse.

Surprisingly, it was believed that an evil spirit having extremely dreadful cursing power turned to the most powerful tutelary god by worshipping the spirit as a god. So Sugawara Michizane come to be worshipped as a god.
By the way, there have been a relic associated with Taira no Masakado, whose spirit is the tutelary god of Edo (old Tokyo). After World war Ⅱ, an attempt to remove the relic ended in failure by a series of accidents.
Although ancient people took too much for granted, it sounds like a good way to eradicate the root of evil. Eventually, it leaves a feeling of awe or respect for the dead.


●sugawara-denju-tenaraikagami(菅原伝授手習鑑)This story was written as a bunraku play by Takeda Izumo(竹田出雲), Miyoshi Syouraku(三好松洛), Namiki Senryu(並木千柳) and premiered in 1748.
I explain the story line: Sugawara Michizane was sent into exile due to a plot by Fujiwara no Shihei(藤原時平), his political rival. Michizane's retainers worked to help him and his son. In the end, Shihei was killed by lightning and Michizane came to be worshipped as a god.

In general, Fujiwara no Tokihira(the name of his role in the play is Shihei) is demonized. However, a TV program shed new light on
Michizane and Tokihira recently. Japanese governing institutions had modeled after Chinese ones, but the traditional system had not worked. In addition, Japan could not rely on the Tang dynasty of China declining at that time.
both of them had felt the need to change the system.