Owh Pina... You could have lived happily in this life if not for your greed... The Kind Emi would definitely support you as a friend, You don't have to fight the Demon King, and if anything, Emi who feel guilty of taking away your "fate" will go above and beyond to make sure you are happy, just like what she did for Remilia...
But here we are... You decide to "return" the plot to it's original path... and worse, it's not the "Remilia" from the game, but the buffed Remilia with knowledge of the "game" that you have to deal with... There will definitely be a Ragnarok happening... The war to destroy the world
EDIT: Ok, after reading the novel, i have to make a clarification. There will be NO Ragnarok... It's so one-sided that i feel a little bit pity for Pina. Just a teeny tiny little grain of salt worth of pity. Cause Spoiler Alert That shit is not Pina, She something similar to Emi, but a lot (and i really mean A LOT) worse. Poor Pina... She got traumatized so bad to the point her soul almost disappear since she choose to disconnect from the body, unlike Remilia who choose to stay with Emi. Pina is 5 years old when that shit took over damn it!