Shifted Senses (Ex):

Electroreception = Electrolocation on table

Levels they are gained at aren't listed in text

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Improved mettle... never thought I'd see the day, but at 20th it's alright.

I'd often thought of creating a reaver class with claws, rake, and some bonuses to hit but this looks much more thought out than that. Seems to address several issues that melee would normally suffer from. I like that you can pick bite or tail because I hate bite attacks but that's just me (I'd never bite anything I don't intend to eat). I feel like races with natural attacks might not gain as many benefits as those with unarmed strikes since you can make 2 extra attacks? Combat monster incarnate as a base class looks good in damage output and chance to hit. Did you potentially factor in shadow blade feat for damage output though? Can't see any serious problems and the class looks much more interesting than a straight up damage dealer.