The father of Nine and Celica, Shūichirō Ayatsuki was a scientist working with Relius Clover before the emergence of the Black Beast. According to BlazBlue: Phase 0, Shūichirō created Kushinada's Lynchpin, referring to it as, "the nail that will nail (the entrance to the boundary) shut". He also made mention of a 'key', referring to it as if it were something to be raised and that the 'lynchpin' was incomplete without it. When Shūichirō first got to work with Relius, he referred to him as a genius. He had a hand in creating a special prime field device requested by a man with green hair. According to Shūichirō's logs, the 'Original Unit' was said to be recovered from the Alucard family. He personally saw Relius getting swallowed up by the Black Beast. He began to panic and decided that using the 'lynchpin' was the best solution. However, the 'key' wasn't there, it having slipped from his grasp. As he waited for his eventual death, the last two lines in his log were, "I can no longer do anything anymore. All I can do now is just wait for my life to end..." (Source: Blazble Wikia)
