Focus on this artwork and explain the Mythos.
Legend claims that a Tennyo goddess named Shichimen  (disguised as a little girl) kept following Nichiren Daishonin who at the time was reciting the Lotus Sutra at the Koza stone in Myosekibo temple (妙 石 坊). Nichiren confronted her, and the mystical figure introduced herself as a water deity seeking to be absolved from past Negative Karma. Nichiren then took a reflective vase (mirror) and placed it before her, revealing her true identity as a red water dragon, gaining Buddhahood at that moment.  Nichiren then instructed her to return to the lake "Ichi—no—ike" and remain there to protect the Kuon Ji Temple. This same deity is claimed to have sent the log of what would become the Dai Gohonzon when Nippo Shonin wanted to carve a statue of his master, Nichiren.According to the doctrines of Nichiren Shoshu based on the Gosho writing Jogyo-Shu-den-Sho, Nippo underwent immense fasting and prayer to the dragon goddess Shichimen, the patroness of Yamanashi prefecture. The goddess, owing her enlightenment to Nichiren, answered his prayer by sending a log in a nearby river. The Dai Gohonzon image was inscribed on a wood log procured from the water goddess by Nippo Shonin, one of his junior disciples. Recounted in the legend:"Nippo (disciple) wanted to carve a statue of Nichiren. He then prayed to (Goddess) Shichimen Dai-myo-jin. Was it an answer (Kannu) to his prayers? He found a log floating in the (river). 
Once stored in the Kuon-ji temple in Yamanashi Prefecture, the image was later confiscated by Nikko Shonin, who designated his strongest disciple, Hyakken-bo to carry the image on his backside through the forest into the Taisekiji complex, where it remains today. Additionally, the statue of Nichiren carved by Nippo from the leftover remains of the original Camphorwood log is stored in a stupa next to the Dai-Gohonzon in the Hoando at Taisekiji.
Accordingly, this mythological account is disputed as one of the many apocryphal forgeries  invented by Nichiren Shoshu according to other opposing Nichiren sects.
Lotus Sutra Taisekiji Camphorwood log Nichiren Daishonin Nikko Shonin apocryphal Yamanashi Prefecture Nichiren Buddhahood Nichiren Shoshu Karma Gohonzon mirror Tennyo