[No System, not invincible, not saintly, fictional setting, one female lead, slow-paced, decisive and ruthless, self-interest above all.]
Long Dan was once the pampered crown prince of the Dragon Clan, doted on by all. But those carefree days vanished forever. Now he must survive in the wilderness. One night, he was ambushed and exiled to a primeval forest for a thousand years. By the time he escaped, the Dragon Clan had been wiped out, leaving him the last dragon in the world. So the young man set out on a journey to uncover the truth behind the clan's extinction.
In a turbulent age, he makes a pact with a rebellious artifact spirit, takes in a mute and clueless little girl, befriends a gentleman who is a tough fighter beneath his feigned propriety, and keeps that reckless musclehead in check.
He personally rises to the rank of a treacherous schemer.
Wherever there's conflict, there I'll be. By my own efforts, I'll earn the title of the Xuanying Continent's number-one troublemaker.
As the only ordinary person on the team, Long Dan says, "Sometimes, being a dragon is really quite helpless."
(The early chapters are mostly worldbuilding and foreshadowing. I'm a new author and accidentally made them a little long, so they may be boring. If you're not interested, you can jump straight to Chapter Nine.)