Odd numbered tails are considered, in the source mythologies, to be significant breakpoints of power and wisdom, especially 5, 7 and 9, what with the beneficial supernatural connotations of those numbers.
If I'm permitted some very quick and dirty powerscaling, 5 is some wizard shit, 7 is archmage shenanigans and 9 is practically a physical god.
Though sometimes they're just correlated with age, like rings on a tree/growth lines on a mollusk shell, with each tail representing a century of lived experience, but that seems to be the minority of interpretations.
Odd numbered tails are considered, in the source mythologies, to be significant breakpoints of power
