Summary: The world is filled with energy that is produced by and sustains life.
Full Details: This is basically the concept of ether/mana/whatever you call it that's the basis of magic in Merlin's canon (and a lot of others, too, when you get down to it). It's produced naturally both in a large scale by the world itself, which could be considered an 'entity' in its own right, as well as in a small scale by living people, animals, etc. Large concentrations of it tend to flow in leylines, and it's known to easily dissolve into some substances such as bodily fluids. Hence why blood is so potent in magical rituals. It's tightly linked with the concept of life, in that the world only produces it while 'alive', and a dead world would presumably be unable to sustain normal life.
That said, it's also notably the power drawn upon to perform feats of magic/magecraft, though as I suspect that may require a second imprint to properly implement I won't go into the mechanics for now! (Though if I'm wrong on that point let me know and I'll write something up.)
Additional Links:Fanwiki entry if you want to wade through a lot of obtuse tl;dr on the topic. See also here for a blurb on "True Ether" and "Grain" for two more variants of it to give an idea of the interconnectedness between "magical energy" and life.
Other: Merlin's canon uses uh, a lot of different names for this stuff. Technically every name means something slightly different ("mana" for the untapped ambient energy in the atmosphere, "od" for that within an individual person, etc) but it's basically like how "nimbus" and "cumulus" are names for different kinds of clouds. If you're going for the very broad concept of "cloud" in general, the fine distinctions are a bit meaningless! With that said, I would suggest using either "mana" and/or "ether" as the name of the concept, if one is needed.
Canon Imprint
Character: Merlin
Canon: Fate/Grand Order
Imprint Type: Concept
Regain?: No
Influence: Link
Summary: The world is filled with energy that is produced by and sustains life.
Full Details: This is basically the concept of ether/mana/whatever you call it that's the basis of magic in Merlin's canon (and a lot of others, too, when you get down to it). It's produced naturally both in a large scale by the world itself, which could be considered an 'entity' in its own right, as well as in a small scale by living people, animals, etc. Large concentrations of it tend to flow in leylines, and it's known to easily dissolve into some substances such as bodily fluids. Hence why blood is so potent in magical rituals. It's tightly linked with the concept of life, in that the world only produces it while 'alive', and a dead world would presumably be unable to sustain normal life.
That said, it's also notably the power drawn upon to perform feats of magic/magecraft, though as I suspect that may require a second imprint to properly implement I won't go into the mechanics for now! (Though if I'm wrong on that point let me know and I'll write something up.)
Additional Links: Fanwiki entry if you want to wade through a lot of obtuse tl;dr on the topic. See also here for a blurb on "True Ether" and "Grain" for two more variants of it to give an idea of the interconnectedness between "magical energy" and life.
Other: Merlin's canon uses uh, a lot of different names for this stuff. Technically every name means something slightly different ("mana" for the untapped ambient energy in the atmosphere, "od" for that within an individual person, etc) but it's basically like how "nimbus" and "cumulus" are names for different kinds of clouds. If you're going for the very broad concept of "cloud" in general, the fine distinctions are a bit meaningless! With that said, I would suggest using either "mana" and/or "ether" as the name of the concept, if one is needed.