He was created by writer Archie Goodwin, and first appeared in Nightmask #1 (November 1986), a series which was published under Marvel's New Universe imprint.
As a consequence, the 'Gnome' storyline which began in issue #1 was abandoned and subsequently ignored until long after the series' cancellation, finally being resolved in Untold Tales of the New Universe: Nightmask (published in 2006).
The series was cancelled after 12 issues, although Remsen continued to feature as a significant New Universe character, with a supporting role (and occasional back-up stories) in other titles.
In 2006, Warren Ellis and Salvador Larroca introduced a different version of the Nightmask character when they revived the New Universe concepts in a new series, newuniversal.
Izanami Randall, who first appears in newuniversal #1 (February 2007), is a young Japanese-American woman living in San Francisco.
After the White Event, Izanami discovers that she has been appointed as the Nightmask and has gained the power to manipulate the "superflow", a "transuniversal space" through which dreams, ideas and telepathy interact with the physical world.
[2] After the Black Event, in which the city of Pittsburgh is destroyed, Teddy is left in a coma, and Remsen becomes one of the first paranormally gifted people drafted into the military.
The attempt fails and Proteus strikes back - Remsen appears to suffer a heart attack, but is unclear whether or not he survived.