Parental Abandonment: His mother is dead and his father is a high ranked Colonel who works abroad in the military. What's more, his mother was a German noblewoman who never was accepted by Japanese society, so she had to leave baby!Shinobu with the Iijyuin clan, which leads to him being...
Star-Crossed Lovers: He and Benio, after he loses his memories. They get better, though. Also, his parents were those as well, since his mom was a German noblewoman, and they were in love, but didn't marry due to her heritage and social standings.
Trauma-Induced Amnesia: During the fight in Manchuria, which causes a lot of trouble in his relationship with Benio.
Uriah Gambit: He subjects to this by an army major who holds a grudge against him, which is the reason why he's sent to Machuria to fight.
Star-Crossed Lovers: Shinobu's grandmother and Benio's grandfather. They were in a Perfectly Arranged Marriage, but were torn apart by political/social standings (One family was pro-Shogunate, another supported the Meiji Restoration), which is the reason why the arranged marriage to Benio and Shinobu happened, so his grandmother would this as a sort-of solace.
Meaningful Name: The first part of his name means "orchid" and the second part means "perfection". Also, his name is probably taken from Mori Ranmaru, the wakashu and most trusted servant of Oda Nobunaga.
Loving a Shadow: She falls for the amnesiac Shinobu because she looks like her dead husband Sasha. And even more: Sasha is Shinobu's half-brother, which is why she sees the very strong resemblance between Shinobu and Sasha.