It was a completely unprecedented development.
Baltamiros was already one of a kind, a God unlike any god in existence.
His power level was an entire qualitative upgrade higher than all the other gods, and although gods granting mortals a portion of their power was not an uncommon occurrence, none had ever done so in such a stupid manner that jeopardized their own side of the deal.
But Baltamiros was a sincere God who would rather suffer a loss than deviate from being true to his own heart, so he did what he felt like doing, and that was to take the once in a lifetime opportunity of combining his newfound power with the process of Elliot's rebirth.