With Grixis Death's Shadow and Dredge occupying spots in Modern's top tier, graveyard hate is now at a premium. Part of the reason Eldrazi Tron has risen in response to those decks is the fact that it can seamlessly play some copies of Relic of Progenitus in its maindeck alongside a full slate of hate cards in its sideboard.
But it's not the only deck that can do that in Modern. In fact, it's not even the only Eldrazi deck that can. Before Thought-Knot Seer and Reality Smasher came along to break the format, there was a midrange Eldrazi deck around in Modern that used Processors and Relic of Progenitus to generate easy value alongside the great mana engine that the Eldrazi lands provided.
That deck has evolved to incorporate better Eldrazi, making it less Processor-focused overall, but still enough that the deck plays four maindeck copies of Relic of Progenitus.
And compared to Eldrazi Tron, you're not as dependent on your mana coming together. You can play a normal, Abzan-style game with discard spells, removal, and Lingering Souls while you set up your engine. All the Eldrazi, from Displacer to Wasteland Strangler to the aforementioned Thought-Knot Seer and Reality Smasher, provide card advantage, so they fit naturally into the attrition plan as well.
But should you happen to draw an Eldrazi Temple or two, you can start to go off with undercosted Eldrazi, giving the deck a different look for opponents to worry about. You won't be explosive as Eldrazi Tron, but you can approximate it in some games without having to worry much at all about Ghost Quarters and Fulminator Mages stranding seven-drops in your hand.
Having actual colored mana in your deck greatly benefits the sideboard, where you have access to staples like Stony Silence and Rest in Peace. Knight of Glory is intriguing tech for Death's Shadow decks, blanking all their non-Snapcaster Mage creatures and dodging all their removal save for Lightning Bolt. For two mana, it causes plenty of headaches, and the exalted trigger will help your 4/4s and 5/5s match up better in combat.
This deck isn't particularly new, as it's been around for over a year now, but now may be the time for it to emerge as a great solution to the current metagame.