It's really simple. The last duel of Tendoukon was 295, while last CA match was 282 days ago according to QLRanks. The account you linked was registered 252 days ago.
Therefore, the guy who the QLRanks pages belong to must have changed his name, and either he or someone else made a new account with the old name.
Another example: when luke changed his nick from lukelawlz to luke_ie, a Polish guy now with the nick SCHATTENTOR took his name. As luke was a duel player, and SCHATT is a TDM player, this caused a funny thing: the two pages on QLRanks belong to a different lukelawlz: