The Armanen row was published by Guido von List in 1908 and is his construction. Each character has a historical original and a layer he added.
The character behind it
Is corresponds to the Younger Futhark character whose Old Norse name was iss, meaning ice. The rune poems describe it as a bridge that is broad and bright and cannot be trusted, and the gloss is consistent across the Norse and English traditions. In the inscriptional record it is a single vertical stroke doing ordinary work as the letter I.
What von List did with it
He kept the I value and the name in Germanised form, and gave the character a meaning within his eighteen. A single vertical stroke is the simplest character in any futhark, and von List makes something of that simplicity in his own system; the medieval material does not.
The claim
Von List presented the eighteen as an ancient Germanic priestly alphabet, recovered rather than composed, with its count taken from the eighteen rune-charms of the Havamal in the Poetic Edda. Historians of runology do not accept the recovery claim and describe the row as an early twentieth-century esoteric invention.
Reception
The Armanen row was taken up in volkisch circles and, in the 1930s and 1940s, by National Socialist organisations. This atlas records that plainly, and keeps the Armanen row distinct from the historical Elder and Younger Futharks it borrows from.