Basic Class - Tough Hero

Original document by Dylan Richards (Reddit: u/Altavus, Tumblr: decision-paralysis, Blogger: DecisionParalysis)
Adapted from "d20 Modern" by Wizards of the Coast and based on the "d20 Modern 5e Conversion" by Edward Wilson.

Enter the Tough Hero; durable, full of fortitude and stamina. They are often stunt persons, bodyguards, enforcers, and athletes. Their skin is tough like iron, they are untiring, unrelenting, and shrug off lesser blows. Surrounded by enemies, the Tough Hero laughs as none can bring them down. They are a bulwark for the team, a survivor weathering any storm of bullets.
As the Tough Hero, you you are the team's tank, its brick wall, its shield. You will stand against any onslaught of foe, untiring and meeting it with subpurb resilience. Your fortitude is unmatched, and when there is a moment of calm in the fight, you'll take your second wind and be ready to go all over again. Not even the threat of death can deter you, because you know you'll pull through, remaining conscious through any injury. And once the enemy has ran out of bullets failing to bring you down, you and your team will have survived to deliver some payback.
Table: Tough Hero

Level	Proficiency Bonus	Features
1st	+2	Second Wind (1/rest), Iron Skin, Advanced Class
2nd	+2	Resilience, Untiring
3rd	+2	Advanced Feature
4th	+2	Ability Score Improvement
5th	+3	Extra Attack, Fortitude
6th	+3	Damage Reduction, Steel Gut
7th	+3	Advanced Feature
8th	+3	Ability Score Improvement
9th	+4	Pull Through, Second Wind (2/rest)
10th	+4	Advanced Feature
11th	+4	Resilience Improvement
12th	+4	Ability Score Improvement
13th	+5	Energy Resistance, Payback
14th	+5	Remain Conscious
15th	+5	Advanced Feature
16th	+5	Ability Score Improvement
17th	+6	Bulwark, Second Wind (3/rest)
18th	+6	Advanced Feature
19th	+6	Ability Score Improvement
20th	+6	Survivor

Class Features

As a Tough Hero, you gain the following class features.

Hit Points and Vitality Points

Hit Dice: 1d12 per Tough Hero level
Hit Points at 1st Level: 12 + Constitution modifier
Hit Points at Higher Levels: an additional 1d12 (or 7) + Constitution modifier per Tough Hero level after 1st
Vitality Points at 1st Level: Constitution score + 4
Vitality Points at Higher Levels: an additional 4 per Tough Hero level after 1st

Proficiencies

Armor: Civilian armor
Weapons: Civilian weapons
Saving Throws: Constitution and one other of your choice
Skills: Choose two from Acrobatics, Animal Handling, Athletics, History, Insight, Intimidation, Perception, Society, and Survival
Systems: None
Tools: None

Second Wind

You have a limited well of stamina that you can draw on to protect yourself from harm. On your turn, you can use a bonus action to regain hit points equal to 1d10 + your Tough Hero level. Once you use this feature, you must finish a short or long rest before you can use it again.
At 9th level, you can use this feature twice between rests, and at 17th level you can use it three times between rests.

Iron Skin

When you are not wearing any armor, your AC equals 10 + your Dexterity + your Constitution modifier.
Additionally, you may use your Constitution modifier in place of your Dexterity modifier for calculating your AC when you are wearing armor. Your Constitution modifier is still subjected to the same restrictions as your Dexterity; such that if you only add your Dexterity modifier up to a maximum value, you do the same with your Constitution modifier, and if the armor doesn't add your Dexterity modifier, you do not add your Constitution modifier.

Advanced Class

You must choose an advance class when you take your first level in this basic class. Your advance class represents varied and nuanced expertise, augmented by your chosen basic class. Your choice of advance class grants you features at 1st level, and again at 3rd, 7th, 10th, 15th, and 18th level. At levels 3rd, 7th, 10th, 15th, and 18th you gain hit dice, hit points, and vitality points as dictated by your advance class, not your basic class.

Resilience

Starting at 2nd level, when you are reduced to 0 vitality points but not killed outright, you can drop to 1 vitality point instead. You can't use this feature again until you finish a long rest.
At 11th level, you can use this feature again after finishing a short or long rest.

Untiring

Beginning at 2nd level, you are especially hardy and can keep working for hours. You have advantage on saves to avoid exhaustion.

Ability Score Improvement

When you reach 4th level, and again at 8th, 12th, 16th, and 19th level, you can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can't increase an ability score above 20 using this feature. Alternatively, you can select a feat instead of increasing your ability scores.

Extra Attack

Starting at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.

Fortitude

Beginning at 5th level, when you finish a short or long rest, you gain temporary hit points equal to your level + your Constitution modifier.

Damage Reduction

At 6th level, bludgeoning, piercing, and slashing damage that you take is reduced by an amount equal to your Constitution modifier, minimum 1. This feature can't reduce the damage you take to below 1.

Steel Gut

Starting at 6th level, your determination allows you to shrug off effects that would otherwise harm you. When you are subjected to an effect that allows you to make a Constitution saving throw to take only half damage, you instead take no damage on a successful save, and half damage if you fail.

Pull Through

Beginning at 9th level, you cling to life, even on the brink of death. When you would make a death saving throw that would result in your death if failed, you have advantage on the saving throw.

Energy Resistance

Starting at 13th level, when you take acid, cold, fire, lightning, or thunder damage, you can use your reaction to gain resistance against the triggering damage type until the start of your next turn.
You can use this feature a number of times equal to your Constitution modifier (a minimum of once). You regain any expended uses when you finish a long rest.

Payback

At 13th level, when you take damage from a creature, you can use your reaction to gain advantage on attacks against that creature until the end of your next turn.

Remain Conscious

Beginning at 14th level, when you are reduced to 0 vitality points, you may continue to act as if you had 1 vitality point until you fail a death saving throw. While at 0 vitality points, you continue to make death saving throws at the start of your turn, your speed is halved, and you can't make any bonus actions or reactions.

Bulwark

Starting at 17th level, your hardiness reaches incredible levels. Your Damage Reduction feature now applies to all damage you take.
Additionally, you can spend a bonus action bracing for damage. Until the start of your next turn, your Damage Reduction feature reduces incoming damage by 2 times your Constitution modifier. If you move while bracing, the effect of this feature immediately ends.

Survivor

At 20th level, you attain the pinnacle of resilience in battle. At the start of each of your turns, you regain hit points equal to 5 + your Constitution modifier if you have no more than half your hit points left. You don't gain this benefit if you have 0 vitality points.

Alternative Features

At the DM's discretion, these alternative features may be used in place of, or in addition too, the ones listed above.

Feat At 1st Level

This feature is standard in all my games, but other DM's may not feel the same and may choose to not use it.
At 1st level, you gain a feat.