Kingdom Hearts will celebrate 25 years next year, as the first game in the RPG series, which began life as a crossover between Disney and Final Fantasy, launched in 2002. Disney will mark the occasion a bit early with a “Deep Dive into Kingdom Hearts” panel during D23 this year. D23 is the official Disney fan club, and it celebrates with a convention called D23: The Ultimate Disney Fan Event every other year. This year is likely to feature our first…