52 years ago - Larry Trainor is born.
34 years ago - 18-year-old Larry joins the navy as a combat pilot.
29 years ago - 23-year-old Larry passes through a mysterious spatial anomaly while flying an experimental quad-fusion fighter. His essence is lost in a mysterious soul form. Niles Caulder manages to contain his disembodied spirit within his own body, which is seriously irradiated.
17 years ago - 35-year-old Larry's body is destroyed in the same explosion that "killed" the original Doom Patrol. His soul-self bonds with Valentina Vostok, their identities blurring.
9 years ago - 43-year-old Larry's soul self is extracted from Valentina Vostok to save her life, and is placed in stasis.
7 years ago - 45-year-old Larry's soul-self begins taking control of suspended bodies, and thus becomes Negative Man again.
The fun of the Doom Patrol comes from their completely surreal concepts and the dark, pulpy adventures they find themselves embroiled in. They're comics specifically for people that are already deeply invested in the world of comics. Negative Man is a great example of that. Unlike Robotman, who is essentially Frankenstein, there's no real allegory for the character outside of comics.
The essentials of the concept are sound. A gritty adventurer becomes an irradiated monster. There's little else to explain. His soul self powers allow him to take a wide variety of utility roles on a superhero team, but they aren't the sort of powers that provide any sort of wish fulfillment.
After the tenure of Negative Woman we're introduced the idea that his soulself is in fact his actual self, and that his time bonded to Valentia Vostok meant that his own identity becomes something fluid. Questions about the nature of identity were a central part of Morrison's Doom Patrol, and the idea that Larry begins to use suspended cadavers as his vessels opens him up to having his own identity constantly in flux, calling into question everything he knows about himself. It's not a far leap from the ideas that were actually at play in the comic, but we like how it takes those ideas and puts them on display a little bit more.
One idea that is pretty clear in Larry's current condition is that it obviously can't continue. something is going to change, and Larry is going to have to make his peace with it. The inherent fatalism to his story serves as a clear doorway from the Doom Patrol's current status quo into the new team lead by Beast Boy.