10 Obscure Comics Secrets That Took Years To Discover
2. The Yellow Impurity Problem
Time To Discover: Oct '59 - Mar '94
When DC entered the Silver Age of Comics, the company did so by changing up the entire mythos of the Green Lanterns by establishing the Green Lantern Corps, the Guardians of the Universe on Oa, and the Central Power Battery. Hal Jordan became the Green Lantern of Sector 2814, and a new mythos was born.
The original Green Lantern had a weakness against wood, but for Jordan and the rest of the members of the Green Lantern Corps, the weakness was against the colour yellow.
This so-called Yellow Impurity limited a Lantern's ability to attack or defend against anything yellow, which became a problem when Sinestro got his hands on a Qwardian Ring, which used yellow instead of green as its power base.
For years and years, the source of the Yellow Impurity remained unknown, or, at the very least, an undeveloped concept. That changed when Hal Jordan lost his marbles and destroyed the Central Power Battery on Oa.
When he did this, he unknowingly released Parallax, the personification of fear in the universe. It was Parallax who introduced the Yellow Impurity into the battery, and when he was released, the only Green Lantern left, Kyle Rayner, the newest member of the Corps chosen after its destruction, had a complete immunity to the Yellow Impurity.