Like most One Piece TCG cards, the value of Sengoku depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Starter Deck 33: BLUE Kuzan)
Also, this is a list of cards for the 99 of Commander decks, not cards you should choose as your commander
All three versions are getting cheaper as time passes, and as this set stays in print, the nonfoils, the traditional foils, and the surge foils are all going to trickle downwards in price
Whenever any player sacrifices a dork, gain a life and put a +1/+1 counter here, all working well with popular deck archetypes
Last year we saw the first ex card for Mamoswine, and the first ever Gourgeist ex was just announced for Japan's upcoming Ninja Spinner set
Fulfilling that role to much success is Drampa from this very set