Aye! I agree (If I get accepted). Anyway, first of all I'm going to explain my idea of Mana:

It's a fuel and a force in of its own. A literal substance. When it first comes to the world it will be pure and without influence. Much like wood is wood, mana would be mana with 4 states of matter: Solid, liquid, gas and plasma. Pure mana can be very easily manipulated through conscious will or belief. So living, thinking beings like humans, animals or anything else can manipulate mana. Deliberate or accidential. For example: if a whole tribe believes mana is warm, mana around them will be preceived as warm. Should a tribe pass that believes mana is cold, then the mana in the area will cool down. If they believe mana is only solid, mana will only be found in a solid state.

However, mana in of itself can also be influenced by an area without a consciousness manipulating. Mana that travels through a forest will pick up attributes of that forest. Like smell or color. Maybe it becomes akin to a tree.

In the end, mana can be used to maintain higher levels of magical influence. It enhances all that its creator choses to be magical. It has a synergy with the Might of gods. Meaning that if a God choses, he/she/it can certaintly use mana around them. This will mean that more mana floods to them. The opposite can also happen. Should a god hate mana, they will repel it wherever they or their creations go. Accepting or denying the gift of mana has no inherent advantages or drawbacks.

My god will be introducing the substance in the world. As well as hold final control over it. Mana often 'returns' to him in a way. Changed, altered. He observes how the world changes through his substance. Maybe a world of war has made it hateful. Or a age of peace, beauty, intelligence had made it enlightening. In the end, he wants to explore the possibilities of this miraculous substance.

My only fear is that this might still tie in a little too much with the innate magical abilities of a god. I picked supernatural as it can break (some) of the laws of nature. It also felt closest to the domain I wanted to pick initially: Magic. Though from reading a little bit more I figured magic wouldn't be accepted as all gods can seemingly use magic through their Might. Cappy, if you want we could discuss some things over Discord as that makes communication a lot easier and we don't end up spamming the OOC?

[b]EDIT:[/b] [@Double Capybara] Maybe your goddess could be his mommy!?

[b]EDIT 2:[/b] an added part to mana: As said earlier there are no inherent advantages or disadvantages to taking or not taking up mana. Those who want to use it in synergy with their own divine power will see that their power is just a little stronger. It will take on their attributes and properties and will thus become a very easy substance to use. While not using/hating/repelling it will mean that mana will go away from your lands or whever you go or have influence over. The advantage to this is that mana will not cause accidents. It is not always so docile as one would believe it to be. For example: a god of light could use mana to create numerous bright lights floating around. However, these lights could end up burning or blinding followers at random.