@lennyfan,
Doesn't really make sense at the moment, but it's 50/50 unless there is some other twist to it.
Here is what I speculate:
If they were different, the angel one gets tossed back in.
But if they were the same, the devilish one gets tossed ... what if he drew out two angels instead of two devils? there is no devilish one to toss back into the box, so he would have no choice but to keep both angels... or would both Angels go back into the box? And although it mentions the extra devilish Usukis in a bag, it clearly says "every time he'd reach into the BOX". I assume that we don't include the extras in the bag at all.
Discounting the ones in the bag, there are 176 in total.
Angel + Angel = approx. 18% (still trying to work out whether both angels are sorted or both go back into the box)
Angel + Devil = approx. 36% chance
Devil + Devil = approx. 32% chance
There is a higher chance of two same ones being chosen [(angel + angel) + (devil + devil)] , so a devil would be tossed back into the box more often.
The odds favor the Devilish Usuki being left, but I am not entirely sure if I'm on the right track with this.
-V