It's an interesting idea, but that is WAY too generalized for my tastes, if not also OP.
An elite phase dragon, which is affected by shields, is worth 14
, for 10/6.
This, with 8/8, is 9
, and cannot be affected by any negative effects.
Using Anubis as a base, because it has a similar attack and cost, this card would be MUCH stronger. I am also not considering the fact Anubis is mainly a support card, and this card would be independent, of course. The ability has to be changed to something more specific.
If I remember correctly, Athena is the Goddess of Knowledge and Strategic Warfare. With this, couldn't you make an ability like Heart of Fire:
All creatures on your side gain +1/+0