-.- I asked for detail, this is nothing of it. Time to add my input, you only explained the base of dark release, there is so much more to it then that.
Meiton is a KG in which the user acts almost as an Organic Fuuinjutsu of sorts, absorbing and releasing physical and spiritual energies (chakra). Because it works, in a sense, like a Fuuinjutsu, the absorbed chakra doesn't actually enter the users Chakra Circulatory System (like what happens with the Rinnegan's absorption abilities) but its kept in the KG mark, as if stored in a separate space within the body. One can say the squares (upper and lower) are much like portals to the sealing space but the sealing space has no connection with the user's chakra. Because of this, the user has little control over the form he can release said chakra. As he releases it, it manifests in a raw energy form rather than a specific elemental one.
Good.
That is correct.
Yes, Hiruko is the one who uses it, he used it via the Chimera Technique, to change his chakra type to Dark, Steel, Swift and Storm.
Okay, I shall explain the strength and weaknesses of our KG.
Dark Release is strong towards energy based elements because energy absorption is the core ability of dark release. Not only that but Energy is easier to absorb and manipulate than matter. Another thing, Dark is able to absorb things like; Storm, Dust, Scorch and even raw Sage Jutsu.
But when release your opponents technique, if your opponent blocks using any of the following; The four obvious ones; Fire, Lighting, Wind and Raw chakra along side these more uncommon ones; Sand, Rain, Steam or Boil you will have the upper hand, since dark just eats right though energy based chakra.
While Dark isn't strong against Water and Earth since they are both matter elements and, lets be real you can't absorb something that is matter, just doesn't work like that. Earth suffers double strength towards the absorbing ability of Dark Release (meaning that only an S-Rank Dark release can absorb a B-Rank Earth technique)
And again when release your opponents technique. If your opponent blocks using any of the following; The two obvious ones Earth and Water as well as; Solid Ice, Steel, Wood or Lava. They will overpower your dark as they are matter based.
The reason I like dark release, it gives you the chance to absorb your opponent attack and redirect it stronger.
Let me ask you this, what is the usual color of dark based chakra attacks?
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"Ciberr asked me; can "Inhaling Maw" absorb dark release chakra? I think so, but not sure."
Yes it can, it can absorb any raw form of energy, even if it was Dark Release energy, when Dark Release absorbs something then releases it, it releases it in the form of enhanced raw energy, other techniques are the same thing as well, ofcourse all following the appropriate ranks.