Wait. ‘Dragon’ is feminine in Welsh?
The big dictionary GPC says it's either feminine or masculine.
(The other two I checked only have it as feminine, though.)
GPC often lists all possibilities from throughout a word's history. Other dictionaries usually list the most commonly found characteristics today i.e. that draig is feminine.
Indeed it is, though I think it was used to mean a leader in the past and I guess it might've been used as masculine then (don't quote me on this I just remember that from a big dictionary once).
You're right about it meaning that. Check out meaning 2: http://geiriadur.ac.uk/gpc/gpc.html?draig
Y ddraig dw i ;)