Wild Speculation - In an effort to stop one of L-Elf's plots, Shouko somehow gets absorbed into Haruto's Valvrave. She literally becomes one with the Valvrave (so that
Elemental Gelade comparison may be an apt one
).
Haruto goes all "I must avenge Shouko!" again, and so he gets into his Valvrave, preparing to kick serious Dorssia ass. Then as he's tearing up, Shouko appears to him in ethereal form, wrapping those glowing ghostly arms around him, saying "It's Ok. I'm here with you, Haruto!"
Haruto's tears of sadness turns to tears of joy, as he's so relieved to discover that Shouko is still alive... albeit as 'the spirit' of his Valvrave!
"Let us save JIOR...
together!" Shouko says.
"Right!" a choked-up and inspired Haruto replies, as he rides Shouko (i.e. his Valvrave) off into space, to combat the Dorssian army.
If the speculation holds true, Shouko may or may not turn back into a normal girl through some elaborate plot device at the end of the series (given the tone of this series, I'm guessing she will turn back into a normal girl at some point, if the speculation holds true).