so I'm assuming for this one he won't try to save the world that much

Sally doesn't really fit ngl unless you make her a god. Also personally I think it would be strange for Hestia since she treats every god as her sibling more than anything else in the stories idk. So Athena for me makes the most sense.

Blood bending seems somewhat realistic since it is liquid and in the PJO series it is shown to be liquid not just water manipulation.

It's a bit contradictory giving the excuse of it not being a harem because itachi isn't that type of person but stating it might not be Itachi in the synopsis. It really just isn't Itachi I kinda just felt insulted that you described itachi's character like this.