Magnetic Malevolent Marauders: Doctor Polaris & Knodar

Neal Emerson was a prominent physicist of Earth-One with a traumatic past. Born Baxter Timmons, he was exposed to severe physical and emotional abuse by his father, which left vast emotional scars on his psyche that would manifest years later. Renaming himself Neal Emerson and scrubbing his past history from the public record, his attained a doctorate as a research scientist. Doctor Emerson sought to incorporate his cutting edge research of magnetism as being a cure-all for health ailments. However, prolonged exposure to this radation left his mind fractured, forming a Jekyll and Hyde split personality. This led to his third identity as the sinister Doctor Polaris

Knodar was born in the 25th century of Earth-Two, during a time when there was virtually no longer crime nor criminal intent in society. However, Knodar was consumed with a desire to become a master thief like the legendary outlaws of the 20th century, and so designed a time-traveling machine. This device allowed him to travel from his native era of 2447 to 1947, where he brought along with him a metal-controller wand allowing him to manipulate metal with magnetic fields under his control.

Doctor Polaris immediately came into conflict with Hal "Green Lantern" Jordan, and despite his potent magnetic weaponry the villain was defeated by his new found foe. Shortly after this, three ancient entities who previously battled Green Lantern and his Justice League allies attempted to escape their imprisonment by animating the Leaguers' costumes with a form of magnetism. When this proved unsuccessful, the three being then animated the costumes of five criminals who previously fought the individual Leaguers, which included Emerson. 

A new faux-Doctor Polaris battled Green Lantern and like his fabricated fellow fiends was defeated. However, unlike the other four faux-foes, this second Doctor Polaris remained alive and assumed Emerson's original identity as Baxter Timmons*. The Earth-Two doppelgänger of the original Baxter Timmons/Neal Emerson was amateur scientist Percival Plazchek/Percy Playboy, who became Nuclear the Magnetic Marauder… a foe of Wonder Woman.

Knodar immediately upon his arrival to 1947 faced Alan "Green Lantern" Scott, who along with a law enforcement officer named Dalmyr of 2447 were able to bring Knodar to justice. However, the criminal escaped captivity in the 25th century and returned once more to the 20th century, this time encountering both Green Lantern and a science counsel teacher named Rhys. Together, the pair were able to outwit Knodar once more, although the miscreant from the future was still undetered and would return a third time where he would attempt to recruit a notorious femme fatale to his cause. Little did he know that he accidentally enlisted the aid of movie actress Ann Hunt instead of the infamous Black-Eyed Bandit, who tipped the battle in Green Lantern's favor.

And Knodar returned once more to the 20th century, this time arriving in Los Angeles, California in 1985 during the Crisis on Infinite Earths. This time as on previous occasions, his schemes ultimately failed, although the dynamic duo who vanquished him was Star-Spangled Kid and Jonni Thunder. 

* Just as Baxter “Doctor Polaris” Timmons was spawned as an adult having skipped childhood on Earth-One, so too was the Sinestro clone of Earth-Two spawned as an adult having skipped his own childhood. Their counterparts of each others’ Earth, the original Sinestro and Knodar grew up from infants and aged naturally, until they became the menacing marauders whom the Green Lanterns repeatedly had to deal with through the years.