I’m thinking a secret skill of instant dreamhunt would do him well. Help with the hg monsters
Put it this way. If I had both stratus and oni, I would pick strat everytime. Legends with similar skill sets I don’t think should have that much of a gap in usage. I honestly don’t think excessive force or at least fighting spirit would make him OP either. But Ive been vouching for Oni and baha for a buff, but baha is a different story 
Double dreamhunt.
Purify;)
Baha & saintfeather are lost cause.
And buff for oni or ss ,
Instant dreamhunt is too much imo,
How about link purifying mist
It purifies one ally , restriction will be 150 seconds after users first turn
Cost 15
How about that ??
Yea, make it OP 
Giving oni purity will make him better than startus. That’s what he needs. Purity
Purify on a OoO monster is to much. I like the swift dreanhunt idea as SS. Maybe even hypnosis (100% sleep) for a 2nd chance to sleep.
nighmare grip
It’s no different from them sleep immune FL. At least f2p player will be able to keep up. Plus sleep FL are so dead oni need that purity SS
Actually come to think of it, a backstab or even Swift canabalize might do the trick. Help charge him and if he uses OoO he can quickly get in a purifier in the 5th spot without making it a purify monster. A less powerful SS would be an instant switch friend.
I’ve always liked the idea of swift toxic killer. Something to help it get a second kill and helps deal with various counters like Freezecobra and various monsters with poison gas.
Lots of secret skill ideas for Oniblade could make it overpowered.
I actually really like that idea but it would alter his play style for sure because there’s not many toxic killers out there anyways.