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Isaiah (Japanese: イザキ Izaki) is a character of the day who appeared in Clamperl of Wisdom.
He runs his own research laboratory and museum on Maisie Island, which hosts several Clamperl in a pool enclosure. While diving off the coast of the island he discovered a blue pearl, similar to those made by Clamperl. He wanted to do some experiments on it so he could discover more about the object. However, when Team Rocket overheard him talking about the pearl, they sneaked in and stole it.
Along with Ash, his friends, and Spoink, Isaiah found the pearl inside of a wild Clamperl, which believed it was its own. Once again, Team Rocket intervened and stole the Clamperl, however, the kids didn't give up, and were able to rescue the Pokémon.
Spoink was able to convince the Clamperl to give the blue pearl back to Isaiah. Now with his pearl safely returned, Isaiah began his research on it while the kids continued their adventures in Hoenn.