Long before Hush became a mainstay Batman villain, Superman had his own ally turned villain who terrorized his personal and professional life. Ruin was a mystery for a long time, and even Superman thought that his best friend from his days in Smallville, Pete Ross, was behind the mask all along after Lana Lang (Pete's ex-wife) was threatened. However, this was nothing more than a ploy to catch the Man of Steel off-guard and frame him for taking all of the sun's energy from the people of Earth, a "theory" that was later disproved. Eventually, Ruin revealed himself to be none other than Superman's former scientific advisor and friend, Dr. Emil Hamilton. This was a shock to many, and although the character continued to appear in Superman-related media, he was rarely seen in the comics again.
Thankfully, "Superman & Lois" has a habit of taking Superman characters and turning them on their heads, subverting fan expectations completely. This means that there's no reason the show's version of Ruin would have to be Hamilton at all, but rather a character who already fits into the "Superman & Lois" mold. Ruin could be anybody!
This might be a story that would need more than a single season to tell, but it's certainly one worth pursuing. There's no doubt that of all the modern-day Superman villains, Ruin has the most personal connection to the Man of Steel, making him all the more dangerous.
