nidan verb (lower class) with 'ru' ending (archaic), intransitive verb
get dark after sunset; turn to dusk; fade into twilight
Archaic intransitive verb describing the onset of dusk. In modern Japanese, 黄昏れる is used instead.
See also: 黄昏れる
In classical Japanese, it was read 'tasogaru' and meant to grow dim as the sun set.
nidan verb (lower class) with 'ru' ending (archaic), intransitive verb
decline after a peak; wane; lose vigour
Archaic figurative use, extending the dusk image to a decline in vitality or fortune. Rare and largely replaced by 黄昏れる in modern contexts.
See also: 黄昏れる
The warlord's power waned as if the evening sun were fading into dusk.