Here is adult and muscular Rupert Bear sitting on a chair and ready to tell a story. Created with Hero Forge.

My Fan-Story
Rupert Bear: Well my little friends, which story do you want to hear? How I saved Pong Ping from the Great Dragon?
The Kids: No!
Rupert Bear: How Tiger Lily and I saved the unicorns of Um Island?
The Kids: No!
Rupert Bear: The story of how Bill, Algy and I defeated the Mulp Gulper?
The Kids: No!
Rupert Bear: My adventure with the Yeti Yum? My encounter with the two little aliens? The story of the magic carousel? My adventure with the Stegosaurus Ginger? My adventure with the bigsmall machine? The case of the missing royal dragons?
The Kids: No!
Rupert Bear: Which story do you want to hear?
One little Boy: Tell us how you became big and strong, Rupert.
Little Girl: Yes, please tell us how you became so big and strong.
All Kids: Yeah!
Rupert Bear: Ok, your wish is my command. When I was a young bear, I didn't have that muscle mass yet and had finished school. I felt a real sense of adventure and decided to leave Nutwood and go out into the world. I was determined to seek adventure. My parents were worried, but they gave me their blessing. There was a bon voyage party for me and my parents and friends wished me good luck. And so I left Nutwood and went hiking. I hiked through mountains, jungles, deserts, and went to sea. And whenever an injustice happened, whenever innocent people had to suffer, I was there to help. But there were challenges to overcome, both natural and unnatural. I even almost died trying to help and couldn't just rely on luck. And that motivated me to strengthen my body. I trained in inhospitable areas, in rain, snow and storms. I found strong but noble people and animals who were willing to train me, be it strongmen in circuses and various Senseis in dojos. I was hardworking and disciplined. Time passed and I grew taller, wider and stronger. I became much tougher and stronger to go on more adventures and help people, whether with muscle strength or just by listening and giving advice. Some just wanted to play strength games with me. I made a big name for myself through my good deeds, which even reached Nutwood. I admit, I loved seeing how my body had changed, but I was careful not to let it go to my head, but rather to use that muscular body to protect innocent people and those I love. Finally the day came for me to return home. Although I had always written to my parents and friends, they still couldn't wait to finally see me again. I arrived in Nutwood and not much had changed. It was sunset and the lights were on in my parents' house. I was a little nervous, but I knocked on the door and my parents opened it. I immediately noticed that I had become a head taller than my parents and they didn't recognize me at first. But when they recognized me, they fell into my arms and were amazed at how much I had changed physically. They escorted me into the living room and my friends greeted me. They were the Professor, the Wise Goat, Father Time, Santa Claus, Bill, Bill's little brother Toby, Algy, Freddy and Ferdie Fox, Edward, Tiger Lily, Podgy, Gladwin the Dragon, Sir Claude, Pong Ping, the Sage of Um, Ottoline and Gregory. They were all happy to see me and amazed at my muscle mass. But they recognized that my nature had not changed. I built my life in Nutwood and when I'm not training I'm always ready to do good. But don't imagine that a massively muscular physique makes you invincible or even invulnerable. You have to balance your muscles and your mind, never forget it. Alright, story time is over. I think your parents are waiting for you to return. Have a good night and see you next time.
The Kids: Thank you very much, Rupert!
A Girl: Thank you for the fantastic story.
A Boy: As always, it was fun listening to you. See you next time.

Rupert Bear is originally created by Mary Tourtel