There is a trend in Legends of Runeterra these days: unblockable units are kings. The trend started with the creation of the I/F Elusive midrange, which was one of the first decks to hit Diamond in the early days of the beta. Recent lists, however, have gone darker, pulling from the sadistic nature of the Shadow Isles region and its Fearsome units.
After several iterations of Shadow Isles/Ionia experiments, Australian pro player came up with a list that abuses the Fearsome mechanic through a powerful duo of cards: Mistwraith and Wraithcaller. When played, Mistwraith buffs all other Mistwraiths, regardless of where they are. The 3-mana 2/2 units soon become 3/2, then 4/2, and with Fearsome they can sneak past any defenders with less than 3 Attack.
Wraithcaller, on the other hand, spawns a Mistwraith on its own, which triggers an additional +1/+0 for all other Mistwraiths, meaning you get a total of six Mistwraiths in your deck. And with that, the offense begins.
This early aggro pressure is also supported by Elise, one of the best 2-drops in the entire game. Cheap value spells like Glimpse Beyond and Mark of the Isles make sure you never run out of cards, or have puny 1/1 spiders kill mighty defenders who dared to block them.
If the enemy isn’t dead by the late game, the deck calls forth the infuriating duo of Shadow Isles nightmares: Rhasa the Sunderer and Commander Ledros. The former is the most powerful tempo minion in the entire game, while Ledros is the threat that keeps on returning to slice the enemy Nexus health in half. Both also have Fearsome, so forget about being chump-blocked by some 1/1s — they’re going to eat something big.
Finally, there’s Hecarim, the go-to late-game champion of Shadow Isles. Hecarim is at the same time a solid body for the late game at 4/6, and an aggro mechanic with his free 3/2 Spectral Riders. He becomes even more scary when he levels up: he grows to a 5/7 body and his Spectral Riders spawn as 5/2.
Not only is this archetype of the strongest decks in the LoR meta, but also a rather easy one to play. There aren’t any complicated mechanics, and it’s all about dropping good units and attacking with them. There is some learning curve on when to use spells like Glimpse Beyond or which targets you should prioritize with your removal, but other than that, the game plan is rather straightforward.