So...now the question: What is Yuugen? Here I will insert a shameless cut and paste from Wiki.
Yūgen (幽玄?) is an important concept in traditional Japanese aesthetics. The exact translation of the word depends on the context. In the Chinese philosophical texts the term was taken from, yūgen meant "dim", "deep" or "mysterious". In the criticism of Japanese waka poetry, it was used to describe the subtle profundity of things that are only vaguely suggested by the poems, and was also the name of a style of poetry (one of the ten orthodox styles delineated by Fujiwara no Teika in his treatises).
Yūgen suggests that beyond what can be said but is not an allusion to another world. It is about this world, this experience. All of these are portals to yūgen:
"To watch the sun sink behind a flower clad hill. To wander on in a huge forest without thought of return. To stand upon the shore and gaze after a boat that disappears behind distant islands. To contemplate the flight of wild geese seen and lost among the clouds. And, subtle shadows of bamboo on bamboo." Zeami Motokiyo
Zeami was the originator of the dramatic art form Noh theatre and wrote the classic book on dramatic theory (Kadensho). He uses images of nature as a constant metaphor. For example, "snow in a silver bowl" represents "the Flower of Tranquility". Yūgen is said to mean “a profound, mysterious sense of the beauty of the universe… and the sad beauty of human suffering”. It is used to refer to Zeami’s interpretation of “refined elegance” in the performance of Noh.
It describes her perfectly. It describes the RIDE perfectly. For me, she is Yuugen.