When I played through my gm completely reworked Suishen to still be powerful without being too much, here was his version.
+2 flaming defending Katana
endure Elements (only on the wielder), Air walk 3/day, daylight, Resist energy (cold), see Invisibility (only on the wielder)
in order of killed five storms oni Suishen gained the following abilities.
1st - Flaming Burst
2nd - Bane against the Oni Type
3rd - Keen
4th - True Sight 1/day
I felt this was much more correctly set up for the game, as you don't get Keen till basically the end of the 4th book and the oni bane helped greatly for the few oni we faced through book 4 and what little of book 3 we had it in, True sight helped mostly in the 6th book when dealing with the final oni and his disguises, I felt a high posabilty of death with this build while still being powerful I had died near the end of book three and made a ijutsu strike samurai, even with all that power I died twice in the 4th book, and was the only one still standing against the oni in book 4, I hope this build helps others as they run this fantastic adventure path.
Oh also on the domination topic I believe the way my gm played Suishen when I was dominated was more correct, when I asked why Suishen didn't just take me over, he said Suishen was a proud warrior and didn't care if a lowly warrior like my character was dominated, allowing myself to become dominated made me weak in Suishen's opinion and as long as I didn't attack Amiko he wouldn't care.
