Was just wondering how their magical powers compared, due to a choose your own adventure document claiming Nasu incubi had more raw mana power than dragons, and that read a bit funny to me. Thanks!
Merlin is the
only example that we have of an Incubus (or rather, an Incubus half-blood), and his powerset mostly involves Illusionism.
He has the capacity to project Illusions into anything that qualifies as a Dream; and as "the World of Man" is semantically "the shared Dream of Humanity," everything that he did in the first arc of Babylonia technically classifies as a projected Illusion. That is, his Illusions are so "real" that they can directly exert an effect on physical existences in the manifest reality. Using these powers, he was able to keep Tiamat asleep -- apparently for several months -- while simultaneously posing as Gilgamesh's Caster-class Servant. At the end of Babylonia, he was able to directly overpower Tiamat's Sea of Life -- and Tiamat was at the time in her Draconian form.
The question then becomes, if he can do so much, how does he power it? He can't possibly do all this without mana cost, right? The canonical answer to this is, "It isn't explicitly explained" -- but we do have information to speculate upon.
The first thing to consider is that Merlin was an inhuman existence born at the tail end of the Age of Gods -- and inhuman entities of the Age of Gods often operate by the Principle of Cycles rather than the Principle of Consumption, where rather than being "consumed," resources are apparently reverted to the System of Nature when not specifically in use.
The second thing to consider is that Merlin is an Incubus -- which is possibly a subset of Demons; which are as far as we know a variety of Curse. For Curses, mana consumption mechanics are often apparently "optional" -- where a phenomenon incurred "simply happens" because the Curse is in effect, without there being consideration for whether mana is consumed.
The third thing to consider is that Merlin is at most times physically situated in Avalon, in the Reverse of the World. Assuming that mana is being consumed in the enactment of Illusions, it's entirely possible that it's powered on the energy within his environment, rather than wherever it is that his Illusion is being projected. Alternatively, Avalon is somehow restoring him. (Obviously, this wouldn't help against Tiamat in the endgame, so it clearly isn't a good explanation for his general energy consumption ...)
That said, using Merlin as an example of the powers of a generic Incubus is ... kinda dumb? Merlin isn't generic. He's half-human, for one -- and he mentions that distinct from other Incubi, he's capable of supplying his own ideation. If not for this, he would need to feed upon the ideations of humanity to subsist. He's also accomplished enough an Illusionist to develop his own variety of Independent Manifestation.
Because of the fact that he's able to overcome Tiamat's Sea of Life, I think it's fair to regard him as an extreme outlier.
Ergo, it
isn't fair to presume that because Merlin can overcome Tiamat, all Incubi are magically capable of commanding mana at a greater capacity than all Dragons. That would be akin to presuming that Japanese gingers are fundamentally stronger than Divine halfbloods from Uruk.
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