Takeshi Oga is a Japanese concept artist and illustrator working in the gaming industry. He has worked on projects that include Gravity Rush, Siren 2, Siren: New Translation, Final Fantasy XIV and Final Fantasy XI Online: Wings of the Goddess.
Aside from that, his website provides little information. A number of the images featured on his website are from a project I can’t identify, but they are so engaging that I would like to see it just to see how the concepts were realized.
His website also includes a gallery of drawings and there is an additional gallery of his work on Concept Art World.