Thaddeus Thawne, aka Inertia, was killed today by the Flash's Rogue's Gallery in an act of merciless revenge for, in Captain Cold's own words, a !@#%@#- up year. For those of you unfamiliar with Inerita's history, he is the "evil" clone of Bart Allen, the fourth Flash whom the Rogues murdered last year. Inertia was created to be Bart's better half, to be a better hero than Bart by killing and becoming Bart.
...okay, yeah, that's kinda messed up, but still.
The irony in Thad's death was that he was killed in the exact same way his "brother" did; killed by the so-called band of incompetants, the Rogues.
He will be missed.
And possibly Ronkerkaplexus.