Pixiv user name is 形昇Nishikino, but he usually signs his work as Nishikino形昇 (see post #4182446).

From his commentary it appears Chinese is his native/preferred language, but post #4182873 suggests that 形昇 should be read as "Kadaji (Katachi) Noboru", which is a Japanese reading. The Mandarin Chinese reading of the same characters would be "Xíng Shēng".
katachi noboru nishikino