[quote=@The Narrator]
[@ActRaiserTheReturned] Be creative, it is up to you. I and OP came up with our relics on a mythological/cultural basis and both took a bit of liberty with them, you can make the same with the stones. Zeus is not really a good of electricity, he is more of a King/Judge. The Stones represented divine or regal bloodlines, so perhaps they could also give your char some sort of ability in that sector. Than again you could also go with a more sky focused ability since they were carried by Zeus divine eagles. 
Another idea if you want to go with electricity would be a weapon infused with it. A birthright could also be modern so a magical gun that shoots lightning is not out of the question. It could be forged by Hephaestus out of [url=http://mythology.wikia.com/wiki/Adamantine]Adamantine[/url] and imbued with Zeus divine lightning. All this are just suggestions however, create what you feel is right but be creative.
Also I have a question. You have written that your char is not good at sports yet he has athletics and was somehow able to defeat a whole gang of thugs? 
Also I realize I sound a bit hostile but again, not my intention.

[@Avanhelsing] Sorry if I take to much of a liberty here, you are OP after all :lol
[/quote]

He was able to beat the whole group of gang members because before he was infused with Zeus'es lightning he was just a good looking guy, now he's empowered by Zeus.