Complex sentence: No previous wrestler had ever accumulated so many titles before reaching sumo's highest rank, but the Sumo Association and Yokozuna Deliberation Council insisted that two consecutive championships were required, having demanded the same of Akebono before his promotion.
Split into simpler sentences: No previous wrestler had ever accumulated so many titles before reaching sumo's highest rank. They insisted that two consecutive championships were required, having demanded the same of Akebono before his promotion.