I made Gladiator Fighter good

 All of this is intentionally stronger than every martial subclass combined (except maybe if Techo Knight is allowed). While reading this, remember that this game features spells.

Level 3: Brutality

When you deal damage with a melee weapon, you can put your training of bloodsport into practice to apply one Brutality Effect you know to it. 

Learning Brutality Effects: You know a number of Brutality Effects equal to half your Fighter level (round up). Choose them, and choose another whenever you can learn an additional Brutality Effect. You can change your choices whenever you finish a Long Rest. 

Glory: Brutality Effects have a Glory option, which you can enable on top of the regular effect. You can use a Glory a number of times equal to your Charisma modifier, and regain all expended uses when you finish a Short or Long Rest. When you use your Action Surge feature, you can use the Glory option of any Brutality Effects you use without expending uses of this feature until the start of your next turn.

Weapon Prerequisites: Some Brutality Effects only apply to certain weapons. If a Brutality Effects mentions any weapons in brackets, then it's only usable with those weapons and the Shortsword and Spear weapons. You must be able to use the mastery property of the weapon any of those weapons or the Spear to use such Brutality Effects.

 

Brutality Effects

• Battery (Club, Greatclub, Greatsword; can't be used with Shortsword): The target's AC is reduced by an amount equal to half your Fighter level (minimum AC 1) until they take a Short or Long Rest.
• Glory: The target has the Stunned condition until the start of your next turn. 
• Bleed (Dagger, weapon which deals Bludgeoning damage): On this attack and on any subsequent weapon attacks against the target while the target has the Bloodied condition, apply the Sap weapon mastery in addition to any other mastery properties applied. Whenever the target makes an attack roll with Disadvantage, it takes 1d6 damage of your weapon's type before the attack roll is made. Both of these effects end when the target takes a Short or Long Rest.
•  Glory: The target's current and max hp are both halved, and they can't regain hp until they take a Short or Long Rest. 
• Bind (whip): You pull the target to an unoccupied space within 5 feet of you and then grapple it. The grapple ends early if you let go of the used weapon.
• Glory: The target has the Restrained condition while it's grappled this way, and your melee attacks which hit against the target are automatic Critical Hits. 
•  Bluff: You can activate the Vex mastery property in addition to a different mastery property you’re using with that weapon, and you have Advantage on the next saving throw you make before the end of your next turn.
• Glory: All attack rolls against the target have Advantage and deal an extra 1d6 Slashing damage until the target takes a Short or Long Rest.
• Throat Chop (Mace, Flail): The target can't speak anymore. A Regeneration spell ends this effect. 
• Glory: The target starts harshly coughing blood, causing it to take 3d6 necrotic damage at the start of each of its turns until 1 minute passes or it can speak again.
• Confuse: You move up your Speed without provoking Opportunity Attacks. The target and any creature of your choice who are within your reach during any moment of this movement have Disadvantage on D20 Tests using Wisdom until the current fight ends or you die.
• Glory: Affected creatures subtract your Charisma modifier from their D20 Tests using Wisdom as well as any spell save DC they have until the current fight ends or you die.
• Control (Weapon with the Reach property): If the target moves, casts a spell, or targets a creature other than you, it provokes an Opportunity Attack from you if you're within its reach. Once per turn, you can choose to not expend your reaction when you make this Opportunity Attack.
• Glory:  The target can't target you in any way, nor can it include you in any area of effect it creatures. This effect ends if you end your turn without the target within your reach.
• Cut (weapon which deals Slashing damage): The target takes 2d6 Slashing damage, and takes this damage agains whenever it takes Slashing damage not dealt as a result of this Brutality Effect.
• Glory: The damage is 4d6 instead of 2d6. 
• Decapacitation (Greatsword; can't be used with the Spear): Apply up to two lingering injuries to the target. 
• Glory: Apply all lingering injuries instead of just two, and give the target the Deafened and Prone conditions. Until all the lingering injuries are removed, these conditions can't be removed in any way except with a Greater Restoration spell.
• Deny (Scimitar, Longsword): Choose one of the following actions: Dash, Disengage, Dodge, Magic. You deny that action, meaning that target can't take the selected creature until it ends its turn outside your reach.
• Glory: You deny all of the aforementioned actions instead of just one.
• Dogpile: The target becomes prone. Allies within 20 feet of you who can hear you can use their reaction to move up to 15 feet towards the target and make a melee attack against the target.
• Glory: The allies don't provoke Opportunity Attacks as part of the movement, and can add your Charisma modifier to their attack and damage roll. The target gains the Incapacitated condition until the end of your next turn.
• Envenom (weapon which deals Piercing damage): the target takes 2d6 Poison damage at the start of each of its turn until 1 minute passes. A Lesser Restoration spell ends this effect.
• Glory: The Poison damage dealt by this effect ignore Poison resistance and immunity. While this effect persists, the target hast the Poisoned condition, even if it has resistance or immunity to the Poisoned condition.
• Home (weapon which deals Piercing damage): When you or an ally within your reach make a weapon attack against the target, add 1d6 to the attack roll. This effect ends when the target leaves your reach.
• Glory: Also apply this to all other enemies you can see within your reach, and set the Speed of all enemies within the your reach to 0 until the start of your next turn. 
• Kneecap (Quarterstaff, martial melee weapon with the Heavy and Reach property): The target's speed is halved until they finish a Short or Long Rest.
• Glory: The target becomes prone and takes 3d6 bludgeoning damage.
• Maim (Greatsword, Longsword): The target's speed is halved, its AC has a -2 penalty, and when it takes the Attack action, it can only make one attack. These effect ends at the start of your next turn.
• Glory: These effect end when the target finishes a Long Rest instead of at the start of your next turn.
• Reap (Sickle): Apply all mastery properties you're not already applying to this attack. 
• Glory: If the mastery property forces a saving throw, creatures who must make the save automatically fail it. Multiply any damage dealt as a result of this use of the Cleave mastery property by an amount equal to your Fighter level.
• Rive: You can activate the Cleave mastery property in addition to a different mastery property you’re using with that weapon, and you can add your ability modifier multiplied by your Fighter level to the damage of the additional attack made as part of that property’s activation. 
• Glory: You can move up to your speed wihout provoking Opportunity Attacks immediately before you activate this Cleave mastery property. You can apply one Brutality Effect you know (abiding by prerequisites) against the creature who takes the Cleave damage.
  No matter what, you can only use this Glory power a maximum of twice per turn.
• Rush: You can activate the Push mastery property in addition to a different mastery property you’re using with that weapon, and you can immediately move up to your Speed without provoking Opportunity Attacks and without expending the movement.. 
• Glory: You can use your Bonus Action a number of additional times equal to your Charism modifier (minimum one additional time) this turn. 
• Stagger: You can activate the Slow mastery property in addition to a different mastery property you’re using with that weapon, and the target has Disadvantage on the next saving throw it makes before the end of your next turn.
• Glory: You move the target up to 15 feet. If the target takes falling damage as a result of this movement, the damage is doubled.
•  Stumble (Club, Greatclub): The target becomes prone, and on its next turn, the target can take only an action or a Bonus Action, not both. 
• Glory: Apply this effect to all enemies within reach. If you used the weapon's mastery property to the target, also apply it to all enemies within reach.
•  Skewer (Rapier, Trident, Pike): Add 1d10 Piercing damage to the damage roll, or 2d10 if you're wielding the weapon with two hands.
• Glory: Don't roll any die as part of the damage roll: you automatically roll the highest possible value for all those die.
• Thrill: The targets becomes Frightened of you until you end a turn without applying a Brutality Effect to it.
• Glory: Apply this effect to all enemies who can see or hear you.

Level 3: Survivor of Blood

You gain one of the following features of your choice. Choose one more when you reach Fighter level 7 (2 total), two more at Fighter level 10 (4 total), three more at Fighter level 15 (7 total), and five more at Fighter level 18 (13 total).

Survivor of Blood options

• Brutal Resurgence: Whenever you expend a use of your Second Wind or Action Surge, you regain an expended use of Glory. 
• Charisma Increase: Increase your Charisma score by 2, to a maximum of 30. 
• Repeatable: Increase your Charisma score by 2 on each repeat, to a maximum of 30. 
• Combat Theatrics: Whenever you make a Dexterity (Acrobatics) or Strength (Athletics) check or make an attack roll, you gain a bonus to the check or attack roll equal to your Charisma modifier (minimum of +1). You also gain proficiency in one of the following skills of your choice: Acrobatics, Athletics, Deception, Intimidation, or Performance. 
• Cloak of Glory: When you take the Attack action, you can take the Disengage and Dash actions immediately before you make your first attack. When you use this, your AC increases by an amount equal to your Charisma modifier (minimum increase of one) against attack rolls of creatures within your reach.
• Flourish Parry: When you're hit with an attack roll, you can use your reaction to add 1d8 to your AC until the end of your next turn, potentially causing the attack to miss. If the enemy is within reach of a weapon you're holding, you can take the Attack action as part of this reaction.
• Immediate Rest: As a Bonus Action, you gain the benefits of finishing a Short Rest. Once you use this feature, you can't use it again until you finish a Long Rest.  
• Phasing Splendor: You're immune to the grappled and restrained condition caused by creatures within your reach, and when your speed would be lowered, you can take a reaction to prevent that. 
• Raise Shield: When you make an attack while wielding a shield, you can forgo the attack to triple the AC granted by the shield when one creature of your choice within your reach makes an attack roll against you. The effect ends when you use this option again. 
• Sturdy Stature: At the start of every turn, you gain temporary hp equal to twice your Fighter level if there is an enemy within reach of you.
• Repeatable: Whenever this option grants you temporary hp, add your Fighter level an additional time to the amount of temporary hp this benefit grants you.
• Wealth of Durability: When you end your turn, you can roll a number of hit die up to a number equal to your Charisma modifier (minimum once). Add your Constitution and Charisma modifier to each roll. You regain hp equal to the total rolled. You also gain 3d10 additional hit die, and whenever you expend hit die to heal after taking a Short Rest, add your Charisma modifier to the amount healed per hit die expended. 

Level 7: Gladiator's Surge

When you use your Action Surge and make the Attack action with the gained action, add your Charisma modifier to the number of attacks you can make as part of that action (minimum one more). You can apply two Brutality Effects instead of only one with these additional attacks. The additional attacks must all be attacks made with melee weapons.

Level 7: Pursuit

When you would make an Opportunity Attack, you can instead take the Attack action. When you deal damage with an attack you make as part of a reaction, you can set the target's Speed to 0 until the start of your next turn.

Level 10: Blood of Glory

You radiate the pure glory you have on the battlefield, inspiring your allies and terrifying your foes. Allies who can see you gain a bonus to their saving throws equal to your Charisma modifier, and enemies within your reach have a penalty to their savings equal to your Charisma modifier.

Level 15: Soul of Glory

Triple the saving throw benefit and penalty of Blood of Glory.

Level 18: Bloodsport's Roles

As an Action, you can expend a use of your Brutality feature's Glory to cause creatures who can see you to gain one of the following effects. Choose the granted effect for each creature individually.

 

Victor: The creature's max hp increases by an amount equal to your Charisma modifier for 10 minutes.

Victim:  The creature becomes permanently Frightened of you and all your allies. If it has immunity to the Frightened condition, then it can make a Charisma saving throw against the effect (DC 8 + your Charisma modifier + your proficiency bonus). On a successful save, it can't be afflicted by this effect by you for 24 hours. On a failed save, it's permanently Frightened of your and all your allies, ignoring its immunity to the condition.