Both Essence Reaver and Runic Echoes will be changes with upcoming patch 8.10, according to the latest PBE update.
AD carries have very limited options when it comes to building mana items. You have the Manamune and the Trinity Force—sort of. Typically that’s not a problem, because they deal most of their damage with basic attacks and therefore don’t need to sling spells as often as mages and even tanks.
There are some marksmen, however, that do need to sling abilities. Jhin, Ezreal, and Lucian come to mind. They can sometimes run into mana problems in-lane, and only one of them can actually afford to build mana to solve the issue later on. To help those sorts of champions. so both Essence Reaver and Runic Echoes are being reworked.
It’s providing 300 mana and some new item abilities. On top of the mana added onto your mana pool, you’ll also now restore one percent of your missing mana with every basic attack, which is reminiscent of the item’s first ability when it was introduced in season four. Back then, it restored mana based on the damage you dealt, so it’s still a little different. You’ll also now gain a huge burst of attack speed. More uniquely, your basic attacks will refund 20 percent of your non-ultimate cool downs for an eight-second period after using your ultimate ability.
Combined with the base 20 percent cool down reduction already provided by this item, it’s now going to be the burst ADC’s best friend. If you need to sling all of your abilities as a marksman to deal huge chunks of damage, this item is going to be perfect for you.
The item’s passive is different, but unlike the Essence Reaver’s new ability, it’s still similar to the previous Runic Echoes. Now, at 100 charges, your next ability will deal a chunk of damage to nearby targets, just like the old one. But it’ll now deal 250 percent damage to large monsters and refund 25 percent of your missing mana. On top of that, the item now gives you 300 mana, 60 AP, and 10 percent cool down reduction.
These changes must be arriving with upcoming patch 8.10 in two weeks.