It was an un-named [[Angel of Death Metal]], by the name of Stewart, that had enough of being thwarted by invisible equipment--according to his own <i>Monster Diary</i>. Upon witnessing a God electrify a hero|ine--who was named but the Angel consistently references as Incognito--he noticed a temporary wash of color bedazzle his eyes, eminating from the hero|ine's head. Centuries of experimentation led him to the conclusion and discovery that (some of) the invisible barriers protecting mortals could be made visible, when varying degrees of electric current were applied.
The exact steps, conclusions and findings of the multiple experiments cannot be found [[Special:random/talk|here]]. A later dairy<ref> This isn't a typo. The diary referenced and culminating much of the known history of Nimbi was eventually revealed to have been a loose page that had been torn from a diary of unknown origin, and repurposed to scribble a derelict God's grocery shopping list entry reveals that the vile monster had, over an untold amount of time, collected every Nimbus ever created and augmented them so that they would be anything (literally) but invisible. Since then, all Nimbus headgear is designated Neon Nimbus equipment, with the archaic Nimbus designation becoming obsolete.
While the angel initially achieved his goal, as the equipment could be identified by its bright neon colors, the unfortunate by-product was an increase in demand for flashy head gear and the subsequent rise of similar products, with a growing market for reproduction. The new iteration also made it much easier for owner's to locate their Nimbi. Summarized by one God's message to their hero|ine while exploring a dungeon: "It's the only glowing object in the cave you twit!"