Something that thrives in high heat with high concentrations of greenhouse gasses.

And absolutely. Have you Seen what people would do for money?

Personal my bet's on a member of the aquatic kingdom or a corvid of some kind though. Maybe an octopus gets born without it's killswitch in one of those billions of years and takes over the planet.

But who am I kidding, in 10000 years nobody's going to remember there was a border conflict on this planet since we'll have already left this rock to burn.