Team's Mentor fleshed out:
He's 55 now, graying hair, slumped walk, and angry, bagged eyes. In his prime, he was a vigilante. He and his partner worked hard to keep the streets safe from other people like him, and rampant crime. He had the power of flight, enhances strength, and forcefields. He was the city's Shield. His partner had the power of Super Speed, and together they put many criminals behind bars, or specially contained force-style prisons for the super-powered. This went on for a majority of 25 years.
One day, his nemesis [INSERT NAME HERE] set up a trap for them. His partner was killed, and his own powers were drained- only after hours of torture. This was irreparable damage done to his spinal column, as well. He was left without the use of his powers at large [slowly regenerating over time], and without the use of the left side of his body.
Feeling worn down, and defeated, he resigned. He caught word of others trying to fill his gap, but the obituaries started stacking up. He found some courage, and pulled himself from his slump- researching some up and coming candidates who have been sighted [or not- the guy's got killer connections] doing acts of kindness, or strange things having happened... He knew better- and would contact them, try to take them under his wing and teach them the 'ins and outs' of the business... Better yet- the emerging threat of his old nemesis- who after aging is taking a backseat and administrative role to his crime empire. This includes the newly formed private military and R&D company called '[INPUT SOMETHING HERE]' that he runs operations both foreign and domestic.