Ruklit had blundered into selecting his IQ and then increasing it. His original IQ was quite low what it was today, but that was probably because of how IQ was generally measured and how the Chronivac development team all spoke English. As Ruklit was untaught and his society's language was underdeveloped most of the IQ we'd measure today just didn't exist for him. Currently it did as the Chronivac flooded his brain with knowledge. Mostly giving and reinforcing mathematics up to algebra, a working understanding on the English language, and boosting his decent memory and somewhat quick wittedness. This gave him enough knowledge that he knew that he should increase his IQ further. It didn't give him knowledge like Germ theory, but it did give him a good understanding of Calculus and allowed him to see the world and the many cause and effects more clearly.
It felt to Ruklit that he should be going back to the village, and when he did he realized how poor everything was. They were constantly building and rebuilding, but the quality was shit. the floor was literally the ground, the beds were merely just whatever softish material they could find lying around, and just... Everything would need to change. He could see the other villager's pointing to him and saying those primitive words that could only describe so much. It was getting late and most of the hunters and gatherers who were coming back were back... Fewer than he would've liked. Ruklit had scanned everyone other than himself and given them language skills, but kept their reasoning lowered... then having given himself a boost in strength and nourished his body as he left his little... Tree branch he technically called home. He could hear the villagers start talking, actually talking surprised by them being able to communicate more than the mere basics. Consulting the chronivac the average IQ was on the rise as the ability to think in more complex terms allowed them to realize SO much more about the world.
Ruklit said "My fellow villagers! God has bestowed upon me a boon! I've been shown the path forwards, and while the path is hard it's less hard than what we've been living with! Let me lead us and we WILL prosper!" The other villagers looked up at him, and he was larger and stronger than he was before... and he was articulate and had a presence about him...
A disbeliever asked "And what's so special about you rather than us!?! We can all speak now! You just got a little bit of muscle more that's all!"
"Well what would you like? I can ask god for any boon!"
The disbeliever said "Fine, to prove you're a leader how about you ask god to make you a small little girl?" the disbeliever looked smug. If Ruklit did that then while he may have god's favor she'd just be a little girl and be in no position to lead, and if he couldn't he really wasn't that much better than anyone else. The following morning the village saw a new little girl with a look of intelligence in her eyes. The new Ruklit looked the disbeliever in the eyes.
"See Everyone! I am chosen by god, and as punishment for disbelieving god has told me our body types will switch!" The disbeliever was a strong, muscled man who used to hog a lot of the meat hunted. However his body and manhood dwindled as Ruklit the little girl grew into a large beast of a man with a dick who could satisfy anyone in the village, and the disbeliever was now a small little girl who'd need to be looked after. Ruklit smiled with satisfaction... Just a small change and then two delayed changes, and now he could lead everyone into prosperity.