If you're going for a world record, always aim to be the first. If you're the best at something, you can be beaten. If you're the first, no-one can take that away. People may well get to the moon better than Neil Armstrong—quicker maybe, or while doing some wicked sick stunts—but no-one can get there before him. Similarly, now, no-one can reach Paragon level 1,000 in Diablo 3's Hardcore mode before Russian player Nokieka. He is the first.
A few sites have slightly misunderstood what Nokieka's achievement means. Paragon levels are account-wide per mode, and so are shared across all of Nokieka's Hardcore characters. Essentially, he didn't reach Paragon level 1,000 without dying. In fact, his Career page shows a few Fallen Heroes over the course of his Hardcore life.
Nonetheless, Nokieka is now top of the Hardcore leaderboard, sitting on a Paragon score of 1,002, thanks to the boost from his Season 1 characters. In fact, he also tops the Season 1 leaderboard, having reached a Hardcore Paragon level of 948.
Don't play Diablo 3? Paragon levels are accrued by max-level 70 characters, and offer Paragon Points that can be spent on a number of different categories. The difficulty is that each subsequent level requires more XP than the last. To reach 1,000, you need 10,311,327,480,000 XP. In other words, that's a lot of Diablo 3.
You can take a look at Nokieka's heroes here. He has one called 'Shitty'. Below, you can see the moment Nokieka reached 1,000.