La carte
Spectral Cloak, ainsi que les cartes
Taoist Hermit et
Zuo Ci, the Mocking Sage, sont les premières cartes à utiliser respectivement les effets des capacités mots-clés
Linceul et
Défense talismanique, bien avant que ces mots-clés ne soient introduits dans les règles via les cartes
Quagnoth,
Troll Ascetic et
Champion's Helm.
Source 1 (Shroud - Hexproof) -
Source 2 (Quagnoth - "[...] the main point of this card's design was to introduce the shroud mechanic.")
Hexproof: Untargetability was something seen in the early days on blue and green creatures. Eventually, R&D decided to put the untargetability naturally on green creatures and enabled blue to add it to creatures with spells and enchantments. This slowly shifted over time until green had what we know today as hexproof and blue had what we know today as shroud. When the ability was keyworded to shroud, both blue and green got the ability. When it shifted to hexproof, blue and green shifted over.