Chapter 6 of Master Ninja difficulty in Ninja Gaiden 2.
Like Mentor difficulty before it, the first three chapters are much harder than 4-6 where you can already be OP. I have enough essence to get out of most horrible situations, and I've been abusing geography a lot (you can backtrack a TON in these levels and take the fight someplace safer, or even despawn enemies altogether).
I hope the rest of the game isn't too brutal, but I'm having a great time. It's funny, this game's Master Ninja is definitely harder than Sigma 2's, but it's also more fair. There are more enemies and they're relentless, but at least I don't have to enter a battle worrying about a OHKO grab/projectile from off screen. The damage enemies are doing right now are a natural increase over Mentor, I feel. Sure, IS ninjas are cheap, but I can be even cheaper with my own tools.
Let's do it!