Is this a joke...? I don't think these races are powerful. In fact, they seem horribly weak. What are they balanced against?Before anyone says that these are powerful, I know.
Without any level adjustment, the Oni might be on par with a Half-Orc. The Arachne could maybe work in a limited way if those seven attacks are abused with something like Sneak Attack. The Nurarhiyon seem just utterly pointless. I mean... they have zero redeeming qualities except that +2 to Intelligence and one of these two points is eaten up by the ability score increase that is lost to the level adjustment.