Kouhei Takeda, aside from portraying Otoya Kurenai from Kamen Rider Kiva, he also lend his voice in Final Fantasy XII for the character, Vaan. With Vaan being announced to be part of the Dissidia 012 roster, most fans assume that Takeda will return to voice the said character, but we are dead wrong.
Accordingly, because of of conflicts with his agency, it prevented Takeda to record lines for Vaan. But because of high demand coming from fans to want him back to Dissidia 012, Nomura decided to include him and his voice actor was replaced by Kensha Ono (Toy Story 3, Harry Potter, Tsubasa Chronicle, Sky Crawlers: Innocent Aces).
Notably, Takeda mentioned in one of his older blog post something like this:
Hey, Square Enix-san. Is that work with Vaan going to appear? I’m waiting (lol)
Source: Kotaku