Plainwalker Of The Stigma summary:

Talented Engineering Professor Wi Geonwoo' was fired from the research center he worked at all his life and was kidnapped by a mystifying light, only to be dropped into a mysterious world. Engineering Professor Wi Geonwoo was approached by an entity that called himself "A God With No Face" and was forcibly given a blue stigma. In this new world, individuals with blue stigmas are hunted, while the ones with red or crimson stigmas are considered the hunters who seek out their prey. Will Wi Geonwoo' with his blue stigma, be able to survive as one of the hunted? "I will be your strength, so lend me your body." To make matters worse, Ash Glaive," a strange slime-like individual appeared. Together with Archmage Ash, and the imagination and monster-like bodies of the engineers, they start the war against the red stigmas.