That said, hooray for new inherent synergy!
I find it strange to consider a cost as "new inherent synergy". New and inherent I can see but usually costs are not called synergistic.
Often with deck ideas and card ideas (I think more the former than latter) I've seen many people say that so and so elements don't have synergy, or don't work together well. My view is that all elements have synergy - but the direct synergy that people often look for I call inherent synergy, because it directly ties the elements together.
I agree that direct synergy is synergy however there is more to synergy than 2 elements being used together. When the use of the second element is a bonus/benefit it is synergy. When the use of the second element is a cost to use the card then it is a cost rather than synergy.
So the inclusion of an off element activation cost is not synergy.
"Requiring Nightfall, Invisibility, Darkness Quanta and, Gravity Quanta are costs"
I see no flaw in what you've said here.
I would use Inherent Synergy to describe when a single card has 2 effects from different elements such that the 2 effects synergize with each other.
"Moving to different slots" and "Automatically attempting to devour opposing creatures" do synergize with each other. However I only see one element (Generic, Gravity) involved.
Direct Synergy I would describe as when an effect on a card has synergy with a card of a different element than the effect on the first card.
"Devour" and "Nightfall (extra hp)"
However a good example of direct synergy would be a card with 2 effects from different elements such that each effect had cards from the opposite element that it synergized with.
I think Inherent counts more for the connection than the extent of the connection (2 effects from different elements such that the 2 effects synergize with each other). This would just end up being called something akin to 'poor synergy'.
In this card's case, it has both a connection with another element (gravity) and with its own element (darkness --> nightfall). Odin could have just created the card with 4/4 | 5/6 stats (current stats + nightfall), and taken off the clause requiring the card itself. The same could have been done for cloak (comes into play invisible). Sure, this would then be a much more viable card, but then what flavor/theme does it have?
I can agree that a cost that is mainly detrimental would not count as synergy. However, I see another side to it, which keeps it in my point of view, still synergy. Continuing my point above, re-doing the card in such a manner would lessen the theme. If we were to remove the detrimental cost, I would see little point to the card at all. The importance then of the ability cost is that of Thematic Synergy.
I would put Direct Synergy simply as just interactions.
