There Is No Need For the Tyrant Second Male Lead's Obsession

I’ve transmigrated into a novel where the emperor, the second male lead, goes mad with war after losing the female lead. And I’ve become an extra princess of a country destined to be destroyed in the chaos.
To survive and protect my beloved father and people, I planned to have an heir to inherit the powers of the merfolk… But the man I spent the night with turned out to be that crazy emperor.
He pretended to be gentle, but became even more obsessed, treating me like an expectant mother? Where did he get the confidence to think I’d be pregnant after just one night?! Please, just set me free!