I don’t think anyone can beat onimaru in this bank except maybe setsuki. And you have to be a rather strong setsuki player to win! Risky move and Knockdown are very strong Onimaru chips. Onimaru can plan to cast risky move 1-2 times without actually buying the chip. Ideally by WTTing knockdown or Gem Essence. Knock down combos extremely well with double slash to give Onimaru a strong rushdown game. Onimaru can buy Ouch which will make it even harder to defend against knockdown=>DS pressure. Ouch WTTs into multiple good things such as GE and knock down (sneak attack also can be good as you can combo it into Ouch for two gems). Its not an optimal oni bank though as it onl has 1 strong 4mana chippe.
Its not obvious to me even setsuki can defend against this. she has a strong lategame but its incredibly good and she needs to get her endgame up and running very fast. Her onl good ramp chips are Risky Move and Draw3. Draw3 is ok if you have a big payoff chip like ICT but there is no such chip. So she probably just has to double take Risky move and walk into the Aggro Onimaru line. Trying to buy OOE and PPK is going to be too slow. However the bank has GE and Draw3. So maybe she can thin deck rapidly into a build that can combine multiple times a turn (maybe just one before it gets going). Eventually setsuki’s goal is to crasha 4 gem every turn. A problem is onimaru can use ouch to apply pressure and add wounds. But onimaru doesn’t have much time before your strategy is running (DT risky mov is very fast ramp).
So I think an extremely well played setsuki can race onimaru in this bank. However Setsuki’s ramp in this bank is extraoridnarily good vs non-aggro. So she should be able to outrun anyone without a powerful aggro line (so not Oni/Midori/Jaina).