How's this for a Challenge 12 martial enemy?
Bang on target. I am valuing Indominatable as worth roughly a third of Legendary Resistance, as it's not nearly as powerful. I also took the liberty of increasing both Strength and Constitution to 20 - fighters get more ASIs anyway!
This could definitely be a legendary knight like Jaime Lannister or Barristan Selmy.
Blademaster
Medium humanoid (any race), any alignment
Armor Class 20 (plate mail, shield)
Hit Points 190 (20d8+100)
Speed 30 ft.
Str 20 (+5) Dex 16 (+3) Con 20 (+5) Int 10 (+0) Wis 12 (+1) Cha 8 (-1)
Saving Throws Str +9, Con +9
Skills Athletics +9, Intimidation +3, Insight +5, Perception +5
Senses passive Perception 15
Languages any one language (usually Common)
Challenge 12 (8,400 XP)
Duelist. The blademaster gains a +2 bonus to damage rolls while wielding a melee weapon in one hand and no other weapons (already calculated).
Superior Critical. The blademaster scores a critical hit on a roll of 18-20.
Action Surge (Recharges after a Short or Long rest). On its turn, the blademaster can take a second action. This feature can be used twice before recharging, but only once on the same turn.
Indomitable (3/Day). The blademaster can reroll a saving throw that it fails. If it does, it must use the new roll.
Actions
Multiattack. The blademaster makes four melee attacks.
Longsword. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 11 (1d8+7) slashing damage.
Reactions
Parry. The blademaster adds 4 to its AC against one melee attack that would hit it. To do so, the blademaster must see the attacker and be wielding a melee weapon.
Bang on target. I am valuing Indominatable as worth roughly a third of Legendary Resistance, as it's not nearly as powerful. I also took the liberty of increasing both Strength and Constitution to 20 - fighters get more ASIs anyway!
This could definitely be a legendary knight like Jaime Lannister or Barristan Selmy.