BUR #47260 has been approved by @evazion.
create implication ninja_gaiden_sigma -> ninja_gaiden
create implication ninja_gaiden_sigma_2 -> ninja_gaiden
create implication yaiba:_ninja_gaiden_z -> ninja_gaiden
create implication ninja_gaiden_ragebound -> ninja_gaiden
create implication ninja_gaiden_dragon_sword -> ninja_gaiden
create implication ninja_ryuuken_den -> ninja_gaiden
create implication ninja_gaiden_4 -> ninja_gaiden
It’s a tiresome task to retag this all the times for ninja gaiden series.