Elden Ring: Rune Thief

"A coward? Good. No one watches a coward." Don Wright transmigrated into Elden Ring as the most forgettable magic apprentice in Liurnia~ right in the middle of the Shattering. He has one secret that would get him executed by every faction alive: every enemy he kills, a sliver of their strength bleeds into him — a heresy the Erdtree would burn him alive for. Now he's a Carian Knight under Princess Ranni, a spy inside the Academy of Raya Lucaria, and the only person alive who knows what's coming — Radahn, Malenia, and the end of the world. He doesn't need to be the Tarnished. He just needs to be alive when they arrive. (Pre-Tarnished Era) — Description from novelcodex.org