But its true. the pace is the combat is distinctly ninja gaiden, the depth of the mechanics are directly from NG. That is without going into the actual ninja skill tree where you can throw shurikens and other projectiles just like NG
Distinctly NG how? the pace of encounters is very different.
Ninja Gaiden doesn't even rely on dividi et impera tactics like this does (since encounters are activated by entering a room).
And the stamina basically ensures that if you get ganged, you'll likely die, Ki Pulse or no Ki Pulse (Ki Pulse doesn't negate stamina completely).
Ninja Gaiden is based around constantly roll jumping around the space and moving, sometimes through the use of the UT's iframes, NioH doesn't allow that, and instead asks you to lock on and funnel enemies, like Souls/Bloodborne games.
Also "depth of the mechanics" is such a generic term that you could lop it at NG, like you could at DMC, Bayonetta or whatever else.
Projectile weapons are also in SoulsBorne games, and AFAIK aren't endless like in NG (well depends on the projectile weapon, but regular shurikens are unlimited).