"The existence of my lover will become a paradox of time. And I can only save her by killing her."
The ending of Echizen Ryoma and Shiina Shizuku was destined to end in despair from the moment the two met.
When the whole world pounces on the people you protect with full malice, what else can you do except compromise? And when you actually change everything, what consequences will the world suffer? Death in exchange for a peaceful world, or death for a new beginning?
It's a paradox and it's also a lover.