This is a posable action figure from the figma series.
From the GoodSmile website:
The next generation male figma model.
A new version of the foundation of all male figmas, the archtype:he is back with more realistic proportions in a gray color great for designers. The figma can easily be used as a model for illustrations or manga, and can also be used as the base for your own customized action figure.
Using the smooth yet posable joints of figma, you can act out a variety of different scenes.
A flexible plastic is used for important areas, allowing proportions to be kept without compromising posability.
An articulated figma stand is included, which allows various poses to be taken.