Tomarishi Shinen is not a known canon character in the Kingdom Hearts series. If you are referring to a fan-made, misremembered, or unofficial character, there is no verified storyline, personality, or role in the official games to summarize. Kingdom Hearts features many original and Disney/Square Enix characters, but this name does not appear in official character lists or major canon references. If you want, I can help identify the closest real Kingdom Hearts character you may have meant.