Find a free, no-strings-attached Knight's Sword in Kingdom Come: Deliverance 2 with this useful location. It's worth the trek.
Walk around with the full protection of a knight earlier in Kingdom Come 2 if you're willing to get your hands dirty.
Moonrithyll's Knight Sword can be obtained by defeating Moonrithyll, Carian Knight, an NPC phantom found in Castle Ensis. Check out the map below for the exact location.