Yeah, agreed with Frettzo. Seeing as Ialu is now close with Vestec, I'd say that Vestec would probably have a part in causing him to ascend. In fact, as you want Ialu to become a god of avarice, I'd say Vestec is a vital component.

Perhaps a god gifting a mortal with his blood would cause them to become a demigod, and gifting a mortal with essence causes them to become a full-fledged god? With the limitation being that the mortal must be extremely powerful already, or they would simply be destroyed.