Tomonobu Itagaki has submitted a number of documents into evidence over his claim of unpaid bonuses and compensation for damages.
Last month, Itagaki quit the development group Team Ninja and filed a law suit against Tecmo's president Yoshimi Yasuda over "unpaid completion bonuses" and for "disingenuous statements" made towards him.
Among the evidence recently handed over to the court was a copy of the contract that supposedly entitled the game creator to a percentage of profits from the Dead or Alive 4 sales, as well as a transcript of a recorded conversation with Tecmo president Yoshimi Yasuda, as reported by Kotaku.
Itagaki claimed to have more evidence, saying: "I am prepared to reveal this evidence as the need arises for the sake of greater justice."
One of the documents, a contract dated March 4th 2005, refers to "special incentives" for Dead or Alive 4 - a program proposed by the former president of Tecmo. The contract supposedly states that Itagaki was entitled to 6.66 per cent of the title's profits.
Further more Itagaki has now increased his claim for damages against Tecmo from JPY 148 million (USD 1.3 million) to JPY 164 million (USD 1.5 million), in order to cover wages he would have been paid had he not been fired.
Among the documents came a reply from Itagaki to Tecmo's, now withdrawn, four point gag order against the Ninja Gaiden creator.
"It is clear that this self-centered behavior by Tecmo Co. Ltd. and its president Yoshimi Yasuda, from the filing of the petition to its subsequent withdrawal, was an attempt to increase my own personal burden in both time and funds needed to combat the petition," he said.
Potentially most damaging to Tecmo's case is the transcript from a recorded conversation in which president Yasuda claims to have been aware that the "special incentive" agreements had been approved by the company's board of directors who signed a ringi - a type of document.
The transcript reports Yasuda as saying: "The board of directors did vote on it and a ringi was signed."