Sousuke Nekome first appears as an individual knowing more about illegals than Haraken (who he speaks to) and is around Tamako's age.
He is later revealed to be the antagonist of the series. He is a former acquaintance of Tamako Harakawa, and the collaborator in Isako's quest to open the door to the "other side." His actual aim is to bring down the Megamass company, due to his father's firing from the company. His brother, Takeru, becomes disenchanted with his older brother's vengeance near the end of the series. Nekome is defeated through the efforts of Megabaa and ultimately his younger brother, Takeru. At the end of Dennou Coil, he tells Yasako that he's going to look for Nekome, who has gone missing.