Hayashikei (ハヤシケイ) also known as Eshijanai-KEI (絵師じゃないKEI, lit. "Not the artist KEI") better known as KEI is a music producer who have created a number of works using Miku, Luka, and VY1. KEI's most notable work is Tower; which is his first work to enter the Nico Hall of Fame. Note that he has no connections whatsoever with the illustrator KEI.
He has earned the title "Legendary VY1 Master" in several of his works such as "ARIGATO" and "Doomsday Clock".