Article from 2015:
https://www.anandtech.com/show/8927/new-challenger-klevv-dram-modules-house-brand-of-sk-hynix
SK Hynix is owned by SK Group (SK C&C), which acts as an umbrella firm over many individual companies. SK Group created a new firm, Essencore, to help bring to market some of the DRAM and NAND capabilities directly to the end-user
rather than through their ICs being sold on the open market. Essencore thus created KLEVV to cover the DRAM side of the equation, kind of making KLEVV a customer/vertical integration partner of SK Hynix, although the two are separate entities under the same umbrella, SK Group. This allows SK Hynix to have more control over their better components coming out of the fabs and sell direct. KLEVV is, on paper at least, another Crucial-like player in the space, and another soon-to-be important DRAM module manufacturer.