Nemesis System (Middle-earth: Shadow of Mordor / Shadow of War)
The system that remembers the orc who killed you and gives him a scar — still under patent for another decade.
US10926179 · Warner Bros. Entertainment Inc. · Active through an estimated August 11, 2036
WB's Nemesis System — the mechanic that tracks individual enemy NPCs across a playthrough, promotes the ones who kill you, and remembers the history between you and them — is covered by US10926179, active with an estimated term through August 11, 2036.
It's the reason you haven't seen another studio ship a direct clone of 'enemies remember what you did to them and hold grudges across sessions' since Shadow of Mordor popularized it in 2014. This is a live patent, not a grave — there's no demo here, and there won't be one for roughly another decade.