This Oni deck got me to master. Any suggestions are welcome on how to improve this deck. Basically play an oni every turn or char to get rid of pesky units. Lots of great synergy on damage boosting and giving overwhelm and card draw. On turn 5 or 6 you should win most games, sometimes even on turn 4 if you can draw Grandmaster Shugo and you played an oni every previous turn.
Now some changes you could think about:
Char - you could have the similar effect with Beaker Blast once you reach 2F and also make the unit voidbound if killed. If you are using it mostly to kill units, you could also think about Bullseye due to it being able to remove relic weapons additionally.
Zealot of Shavkan - I'm not a fan of that card, i would personally prefer Ankle Cutter or Midchief Salus
Shingane Captain - I consider him to be to costly to what he does, you could basicly have the same effect with Mask Maker
Powerbase - Since you are running 27 Power cards, why not swap out 2 of them for Inscribe cards? You will still have your powerbase, yet when it isnt needed to have powercards anymore, they would add gas to your deck. Oni Forgesmith, Final Moments or Draconic Looting would be good picks
All in all I like your deck, keep up the good work
Edit: Xo has Inscribe too, forgot about him
Granite coin and forge for some extra damage.
Granite way stone and emblem of shavka for undepleted extra units.