Jack getting shagged to death was mentioned in one of the Torchwood books :)
Remember the fact that it’s been mentioned that Ianto saw Jack getting shagged to death.
Just take a moment and think about that.
*Squeaks with delight* Gareth David-Lloyd with his daughter, Lilly! So adorable <3
If Jack harkness never existed, Ianto would never have met him.
But the battle of Canary Wharf would have still happened.
He would have no one to turn to in his hopes to save Lisa. He would’ve tried to help her on his own, by her guidelines.
But in the end, she would be well enough to get on on her own. Then she, or the cyberman in her, would’ve killed Ianto and upgrade him.
Thus, forming a new base for the cybermen to upgrade all other humans. Human life on earth would be extinct and earth would be overrun by cybermen.
If Ianto had never met Jack or if Jack had not hired him, human life on earth would’ve ended!