#026: Raichu
Of the three elemental gemstones found throughout Kanto, it is the Thunderstone that is by far the most sought after. They're one of the top prizes that every Itemfinder owner hopes to stumble upon. And this is because there's no other known way to transform a Pikachu into a Raichu.
Raichu are valuable in Kanto because they're the one pokemon in the region with electrical energy that can be harnessed safely by man. Raichu constantly build up power and can release it in a slow and controlled manner through their long tails. While Kanto is home to several pokemon species that like to guzzle up man-made electricity, Raichu more than make up for this deficit: a single specimen can power an entire household.
Of course, lightning is one of the most dangerous forces that pokemon have power over, and no electric type is 100% safe. When Raichu were first hooked up to generators during the industrial revolution, they were generally kept indoors at all times. It wasn't long before it was discovered that not only can Raichu release electricity regularly, they must. If too much power is allowed to build up in their cheeks, Raichu lose control, becoming aggressive, violent even, until it is released. After the first town burned to the ground when a prolonged power cut left nothing for the resident Raichu to charge, it was ruled that no pokemon should be cooped up 24/7. Regular outdoor exercise gives a Raichu's excess lightning somewhere to go and leaves them far healthier and happier.