The Tropius lived in a beautiful jungle in Hoenn with other Tropius and many other native Pokemon. She was rather content with her life, until one fateful day a bunch of TOTAL FUCKING JERKS decided to do some ecoterrorism.
The jungle was destroyed, and the Pokemon were either killed or locked into cages or nets. She managed to fly away, desparately trying to get out of sight. The tropius flew and she flew. She flew until she couldn't feel her wings, and she flew until she felt them growing tattered. And she kept flying, through sunsets and sunrises.
She landed finally on land in Johto. So exaughsted I need a better word, she heard the sound of fresh water in a cave. She went in, took a drink, and then went to bed.
The Pokemon in that cave were curious about the stranger, and could tell how tattered she was. They offered her their home, their food, and their water. This was a new place for her to live. In return, she protected the Pokemon, scaring off foes with her large imposing appearance.
She had many friends in the cave, but most of all was a Wooper. She and the Wooper naturally got along, and they vowed to always stay at one another's side. Often, the Tropius would walk around with the Wooper on her back, and Wooper would jump off to find pathways closer to the ground.
However, Tropius were not built to live in caves. As they are Grass Pokemon they need sunlight to photosynthasize. Without it, the Tropius' leaves grew tattered and yellow. She couldn't fly any longer, but she acted like she didn't mind anyways since she didn't need to fly, as there wasn't enough open space in the cave. Still, her cave friends worried for her.
In a series of events that are like an episode of the anime, Gold ends up lost in a cave with his Pokemon (at the time Silklay, Atticus, Norma, Honoa, and Drugia). A wild Aggron in the cave attacks them, but then Tropius scares off the foe, protecting the strangers.
Once the threat has run off, the rest of the Pokemon living in the cave greet themselves and show them to their home, quickly becoming friends. With their help they were able to navigate their way out of the cave. They ran into the Aggron again, and this time with the Tropius and Wooper's help were able to scare it off for good, protecting the other Pokemon in the cave.
Finally finding their way out, Gold and his Pokemon waved a tearful goodbye to all the Pokemon they had met in the cave, hoping to meet again. As they were walking away, the Wooper had an idea and started running after Gold. Tropius understood the message: Wooper would never go somewhere without her, so Wooper was trying to suggest that she should leave the cave.
Tropius at first was reluctant, as she felt a duty towards the Pokemon in the cave, having protected them so long, but everyone insisted. They all believed that leaving the cave towards the sunshine would be best for her health, and that since the Aggron was defeated they could fend for themselves.
Tearful, but respecting her friend's advice, The Tropius followed after her friend the Wooper.
After having officially caught them both to make them part of the party, Gold was trying to think of different things he could name them. As a joke while brainstorming, he said "Bongo Banco", and the two thought it was so funny that it was decided it would become their names. Bongo the Wooper, and Banco the Tropius.
The next step on Gold's journey was to the Lake of Rage. A harsh rain, strange radio signals, tourists from all over the region, journalists reporting on the event, and an angry Gyrados storming the waters. Gold hadn't heard of any of this, having been too out in the woods to have been looking at the news.
His cousin Tala happened to be there as well. She had actually heard the news during her own parallel Pokemon journey, and had come here to watch. Gold and Tala recognized each other at the crowded lake, and Tala summarized what was going on for him. A red Gyrados was rampaging through the waters and causing the storm in the area. Seeing the opportunity to help, Gold got his surfing Pokemon Honoa out onto the lake to battle it.
Since he had just caught the Tropius and Wooper he had them following him around instead of keeping them in their Pokeballs. When he rushed out to the lake, it was fastest for Bongo to stay behind with Tala, instead of getting returned to its Pokeball.
Once the Gyarados was stopped, Gold went back to Tala to pick up Bongo. However, Bongo decided to stay with Tala. He got along with her and her Marill, and knew that since Tala and Gold were friends that he would easily be able to see Banco again. Banco was a little sad about the separation, but was fine with it, knowing it would mean more personal growth and unique stories to tell each other in the future.
Shortly after Gold had got Banco, he checked in with Professor Elm, who explained that though time in the sun and good watering would help out the plant parts of her body significantly, it may be a long time or possibly never that her leaves are able to regrow to be able to fly again.
Though this news was a bit sad, the thought on giving up on the Tropius never crossed his mind. Whenever he was crossing a sunny route he'd let her out of her Pokeball so they could lounge in the sun together, and would always choose wherever the sun was brightest to stop and eat. He did a lot of research on what would be best to feed her so that her plant parts could grow back strongest, and went out of his way to find the best ingredients from the wild to mix himself.
Gradually, her leaves turned from yellow to green, they grew thicker and wider, and soon enough she was able to start menuvering them again. At first all she could do was simple attacks such as Gust, but with careful training and lots of care, her wings made a full recovery and she was able to fly again.
During the time of the Ukagaka, Banco is doing very well as a member of Gold's team. She gets along easily with the other Pokemon and for Konkurs specifically she is like a Mom. Even while she's made a recovery from the condition her leaves were in in the caves, her physical attacks are still much higher than her special attacks. She was on Gold's team both times he won the Pokemon Master title.