In my campaign, Muerte died back in the Nineties, killed by one of the heroes and left in a strange dimension where that hero got his powers. Terror Inc. broke up, which gives me the perfect opportunity to have Feur and Scorpio join Eurostar.
However, about two years ago Muerte reappeared in Central America and began rebuilding his organization but without contacting any of his old team (including Giganto, who is currently sitting in Stronghold). Oddly, he has exhibited new powers in addition to those recorded, mostly having to do with teleportation and seemingly magical in nature.
What really returned was not Muerte at all, but a creature of the other dimension who is wearing Muerte's armor. It's agenda is different than Muerte's was and it is currently seizing any magical artifacts it can while also creating a number of bases with genetic experimentation facilities and the ability to produce large amounts of protoplasm.
The players haven't encountered the new Muerte yet, but it should be interesting when they find him very different that their research indicates.