BUR #15866 has been approved by @nonamethanks.
create implication kyuubi -> kitsune
As both tags wiki entries state, kyuubi is a "fully upgraded" kitsune, therefore one should imply another.
Alternatively, make both tags mutually exclusive, do a mass update for kitsune kyuubi solo, and update their wiki entries.
Another alternative, based on the fact that many kyuubi posts rely on knowing the copyright and not always show exactly nine tails, is to define danbooru's kitsune as fox or foxgirl with multiple tails and merge two tags together.