Jon decides that there is no point in crying over spilt milk and goes to bed, he'll just have to break the bad news to Karyn in the morning.
Unbeknownst to Jon at some point in the night the stone, now a tablet started to briefly vibrate before lighting up, displaying text. After a few minutes later, it returned to normal.
"Jon, Jon darling, wake up it's important, I just had a revelation."
Jon growns "What is it Zoe? Can't it wait for morning? Is it about that magical stone I killed and you couldn't tell me about?"
"Yes it is."
"Alright then, what did my careless wish earlier do besides making the stone useless? And what was stopping you from telling me then?"
"It's not useless, the way it operates merely changed. Now it will display a bit of text at random intervals, and you're expected to change one word in said text. The previous sentence will become false while the new one will become true. However there is also a timer, and if you don't change a word before it runs out it will randomly change one for you."
"So you've woken me up to warn me before it randomly changes something. Thank you for that."
"You're welcome, but no it already has made such a change. And just like how before only people hearing the wish were aware of any changes, now only people who read the sentence are aware of it's changes."
"But I take it your demonic eyes are working on it once more? So what did it change and why couldn't you see earlier?"
"I couldn't see because I didn't exist yet. I am what it changed, it turned me into your demon servant."
Jon is taken aback, and very concerned.
"Th-this doesn't change our relationship does it?"
"Not at all, if anything I have more reason to serve you. You didn't happen to just save me, you are outright responsible for my creation."
"I see" Jon breathes a sigh of relief, over the last couple of years since accidentally summoning her while flunking his Latin class, he had came to rely on her services and abilities for way too much. Her good looks and loyalty had even driven him to make her his fiancee. Well he guesses that it 's all a lie fabricated by the stone, but still he feels dependant on her. "Out of curiosity, what was the text and what was it changed to?"
"I'm not sure you want to know. If you knew about our previous relationship you might second guess our current relationship. But let's just say that I feel confident in saying that if I was given the choice to stay who I was or to become who I am now, I would have chosen to become who I am now."
"Jeez, now I'm really curious, but I'll trust your judgment. Say are my parents sleeping?"
Zoe smiles at Jon while undressing and sliding under the covers next to Jon "Of course, it is late."
Authors note: so basically here is the idea. The stone is now a tablet that produces random bits of text at random intervals. Anyone who reads the original text will be aware of any changes it makes. When it does produce a bit of text someone needs to change a word before the timer runs out, or else the tablet will change a word on it's own.
For the curious, the phrase this time was "Jon's sister Zoe is goth" which became "Jon's demon Zoe is goth".
The old phrase became false, Zoe no longer Jon's sister. The new phrase became true, Zoe is a demon. To be exact Jon's demon, she belongs to him and is his loyal servant.
Now please feel free to go back and write your own branch. Either have Jon play with the tablet longer untill he sees the phrase pop up and make his own change. Have a different phrase entirely pop up, or continue this branch.
Feel free to even just add a single phrase without any story and see where other people take it.
