This is in mind with the guy from that one elder scrolls video you might have seen - if not google elder scrulls fighter scene (high Ilse launch)

The build isn’t game play ready, I don’t master the dnd beyond tools (AC + dexterity, extra reactions etc). Feel free to change things or to put it into working versions. 

Level 3: Improved critical

Your attack rolls with weapons and Unarmed Strikes can score a Critical Hit on a roll of 19 or 20 on the d20.

Level 3: Level 3: Remarkable Athlete - armored fighting buff

Thanks to your athleticism, you have Advantage on Initiative rolls and Strength (Athletics) checks.

In addition, immediately after you score a Critical Hit, you can move up to half your Speed without provoking Opportunity Attacks.

You always add at least half your dexterity modifier to your AC, unaffected by the kind of armor you wear.

Level 7: Level 7: Improved reaction - actual fighter

As an reaction
- You can impose disadvantage on one melee attack roll within 5ft. of you.
- When an enemy attacks you within 5ft. you can try to parry: Roll a D20. If your roll plus your proficiency bonus exceeds the enemies attack role (plus their modifiers) you can block the attack and do an unarmed strike against the enemy
- When a spell is cast within 5ft. of you that has a target and at least a range of 5ft. you can roll a d20. If the roll plus your proficiency bonus exceeds the enemies attack roll (plus modifiers), you can redirect the spell at the caster.

Level 10: Level 10: Extra reaction

Grants an extra reaction per round.

Level 15: Level 15: Perfected reactions

Your parry attacks can now use your weapon dice without the modifiers instead of your unarmed strikes as you can chose to nick your opponents with your first, or head, feet, etc or with your weapon handle or different parts of your weapon that isn’t a full strike.

Your reaction rolls add your dexterity modifier on top of your proficiency bonus.

Level 18: Level 18: Superior Critical

Your attack rolls with weapons and Unarmed Strikes can now score a Critical Hit on a roll of 18–20 on the d20.