Chanyeol was passionately fond of a youth named Kyungsoo. He
accompanied him in his sports, carried the nets when he went
fishing, led the dogs when he went to hunt, followed him in his
excursions in the mountains, and neglected for him his lyre and
his arrows. One day they played a game of quoits together, and
Chanyeol, heaving aloft the discus, with strength mingled with
skill, sent it high and far. Kyungsoo watched it as it flew,
and excited with the sport ran forward to seize it, eager to make
his throw, when the quoit bounded from the earth and struck him
in the forehead. He fainted and fell. The god, as pale as
himself, raised him and tried all his art to stanch the wound and
retain the flitting life, but all in vain; the hurt was past the
power of medicine. As, when one has broken the stem of a lily in
the garden, it hangs its head and turns its flowers to the earth,
so the head of the dying boy, as if too heavy for his neck, fell
over on his shoulder. "Thou diest, Kyungsoo," so spoke Junmyeon,
"robbed of thy youth by me. Thine is the suffering, mine the
crime. Would that I could die for thee! But since that may not
be thou shalt live with me in memory and in song. My lyre shall
celebrate thee, my song shall tell thy fate, and thou shalt
become a flower inscribed with my regrets." While Chanyeol spoke,
behold the blood which had flowed on the ground and stained the
herbage, ceased to be blood; but a flower of hue more beautiful
than the Tyrian sprang up, resembling the lily, if it were not
that this is purple and that silvery white (it is evidently not
our modern hyacinth that is here described. It is perhaps some
species of iris, or perhaps of larkspur, or of pansy.) And this
was not enough for Junmyeon; but to confer still grater honor, he
marked the petals with his sorrow, and inscribed "Ah! Ah!" upon
them, as we see to this day. The flower bears the name of
Hyacinthus, and with every returning spring revives the memory of
his fate.

It was said that Yifan (the West-wind), who was also fond of
Hyacinthus and jealous of his preference of Chanyeol, blew the
quoit out of its course to make it strike Kyungsoo.

A/N: This story was based on the story Of Hyacinthus and Apollo. Search it on Google to know who they are :D