Dark Release: Inhaling Maw

Hiruko uses the Dark Release Kekkei Genkai he acquired through his Chimera Technique to perform a technique superficially similar to the Chakra Absorption Technique, in order to forcibly extract the physical and spiritual energy of another ninja and absorb it through the upper square of the mark on his left hand. It appears that he is able to completely remove the victim's chakra, potentially causing death. After using this ability, Hiruko is able to detect their natural elemental affinity, and then manipulate the victim's chakra and perform ninjutsu of that element. This allows him to deconstruct and learn the abilities of his opponents, and he can presumably utilize all forms of Nature Transformation as a result.

Trivia

 * Curiously, Hiruko didn't use any seal first time he used the jutsu.
 * When Hiruko tries to absorb Naruto's Wind Release: Rasenshuriken, he is unable to combine the shape and nature manipulation, and the technique falls apart.