Part 1
10 Facts About Sage Oak

Sage has a full profile already, so these facts will be more trivia that can’t be found there.

1. Sage is the second son of Green Oak and Red Aoyama. He was born on March 8, 3620, three years after his older brother, Roy.
2. Sage’s goal to become a Gym Leader is actually in direct response to Roy having the same goal. Sage thinks that Roy doesn’t have what it takes to be a successful Gym Leader, so he wants to become one as well and prove that he can do it better than his brother can.
3. As such, he’s been bothering his Aunt Leaf about inheriting the Viridian Gym from her, though her response is usually “I’ll think about it when you’re older” or “If you think I’m retiring any time soon, think again, kid!”
4. He’s childhood friends with both Scout and Alton, his traveling companions. He’s known Scout longer, since they’re both from Pallet and the same age, but he’s closer with Alton since the two have more in common.
5. He and Alton both vent to each other about whatever problems they have with their parents. Neither are particularly estranged from them or anything, but they both feel pressure in their families to succeed in one area or another and are in similar positions being the youngest child (well, Alton has a younger half-sister, but he doesn’t see her as much since he’s raised mostly by Misty rather than Brock.)
6. Sage has an appreciation for traditional Kantonian culture that’s reflected in his style of dress. While neither of his parents are particularly spiritual or traditional, both of their parents (Sage’s grandparents) were friends with one of Kanto’s major deities. Sage grew up hearing stories about historical eras, spirits, youkai, and the like from his Aunt Yellow and her father, as well as his own great-grandfather Blaine, and developed an interest in Kanto’s history and traditional culture. He loves festivals since to him, they’re somewhat a timeless tradition and depending on the festival, sometimes the Other World is more present than ever. 
7. Sage’s dislike of urban legends is related to this. He hates how modern myths replace the old ones and will never spread an urban legend he hears, even chiding the one he heard it from for believing rumors like that. Similarly, Sage has a fascination with youkai ever since he found out his own great-great grandmother was a fox youkai. He’s cautious about poking his nose too far into such things, however, since he knows it can be dangerous even for mages like himself.
8. When traveling in Johto, Sage’s group encounter Branwen, Corvin, and Celeste, all of whom spend a lot of time investigating the supernatural, urban legends, hauntings, and the like (much to Celeste’s chagrin.) Sage disapproves of their actions since he believes they’re just putting themselves and others in danger by messing with things they don’t understand. He’s rivals especially with Branwen, who’s flippant attitude reminds him unpleasantly of Roy. They battle pretty much every time they meet.
9. Sage has a habit of being very defensive of his interests, especially if they’re more obscure. He tends to criticize more popular trends and media if he happens to enjoy something less popular and will get annoyed if anyone makes the inevitable hipster jokes about this. For example, Sage dislikes the Hoenn Rangers Coexistence Force show only because he likes the older and less popular Kanto Rangers Justice Heroes program, which only had two seasons and barely any merch or dvds exist any more. It’s less that he loves the latter show, and more that he’s bothered that the one he likes more is less popular. He has similar feelings about many other things, like foods, movies, and music.
10. Sage is actually horrible at learning languages. He’s fluent in Japanese (his mother tongue),

    and Japanese Sign Language (what Red uses to primarily communicate) and semi-fluent in League Standard (a language intended for use by travelers that’s standardized across all regions that are part of the Pokémon League, it’s taught in schools and most people are only conversational in it unless they travel frequently.) He chose English as his language elective in school but is miserable at it. He generally relies on his more linguistically-inclined friends to translate if the need arises.