“Questing knights, conquering overlords, royal champions, elite foot soldiers, hardened mercenaries and bandit kings - as fighters, they all share an unparalleled mastery with weapons and armor, and a thorough knowledge of the skills of combat.” - Players Handbook 

The fighter is already an extremely diverse class with a lot of potential for personalization, but multiclassing is a great option if you’re looking to customize your character further.  

Gaining some levels in a different class gets your fighter abilities and features beyond their usual capabilities. While multiclassing is never necessary to play the game, it can add some fun for veteran players and introduce new ways to play familiar classes. 

Your choice of multiclass could be based on what makes sense with the backstory of your character, as a means of adding flavor, or as a way to augment the Fighter class to fit the playstyle you are going for. 

Here are some of the best options for your secondary class as a Fighter. 

5. Fighter/Cleric

It can be interesting to roleplay a character that is a warrior and healer in one, who acts as both destroyer and giver of life. 

You gain some spellcasting, healing abilities, and other domain-associated features from a level or two in cleric, but I wouldn't suggest dipping into it any further. At some point, it’s better to just go with a paladin than a fighter/cleric multiclass. 

Why Fighter/Cleric Is Great

• At first level, you gain access to three cleric cantrips and two first level spells. You can use these spells to heal yourself or party members or to bestow buffs. The way cleric spellcasting works is pretty useful, as you get to swap out your prepared spells from all of the cleric spells that you have appropriate spell slots for. 
• Dipping just one level into cleric also gives you a choice of Domain, giving you quick access to some unique and useful cleric features. Many of them are great, but the War Domain is probably the best for a fighter. You get access to the Divine Favor and Shield of Faith spells, and get the Channel Divinity: Guided Strike ability.

4. Fighter/Warlock

This type of character is a combat expert who has entered into some sort of pact with a powerful patron, using magic to supplement their physical attacks. 

While this can be a cool multiclass to play, keep in mind that it isn't the very best option on this list as some of the Pacts aren’t particularly useful when combined with fighter abilities.

Why Fighter/Warlock Is Great

• You get the physical power of the fighter combined with the spellcasting ability of the warlock, and it's not as redundant as multiclassing in fighter/wizard when there’s the Eldritch Knight subclass option. 
• Eldritch Blast is a great ranged attack option that will continue to be useful as you progress through levels. 
• The warlock is versatile and any multiclass can benefit from even just one level in it. Your invocations can be used to supplement your weapon damage and you also get access to the abilities associated with Patrons. 
• You get the option to take Hex as one of your spells, which adds 1d6 extra damage to a single enemy every time you hit them with an attack. If the target is killed, you can use a bonus action to curse a new enemy. As a fighter you’ll be making multiple attacks a turn with your Action Surge feature, which goes great with a spell like Hex. 

3. Fighter/Ranger

This is one of the more versatile options on this list. While not especially interesting, the ranger does add some dimension to the typically strong but dumb fighter stereotype. If you’re looking to play a solitary fighter with a strong connection to nature and the wilderness, this is the way to go. This multiclass also has the benefit of the rangers spellcasting and archetypes.

Why Fighter/Ranger Is Great

• Just one level in ranger gives your fighter a Favored Enemy. You also get to pick a Favored Terrain, which gives you numerous benefits while traveling through a certain kind of environment. 
• With two levels in ranger you get spellcasting and an additional fighting style. 
• The best spell you get access to at level two is the Hunter’s Mark spell, which gives you an extra 1d6 damage each time you hit the target with a weapon attack. This is especially powerful combined with your Action Surge, stacking a ton of damage over a single turn.
• For archetypes, Fey Wanderer is nice if you want a more charismatic fighter with a connection to the Fey. You get the Charm Person spell and Dreadful Strikes, which deals an extra 1d4 psychic damage when you attack with a weapon. Gloom Stalker gives you Disguise Self, Dread Ambusher, and Umbral Sight. Horizon Walker’s Planar Warrior turns your weapon's damage type to force and adds an extra 1d8 of damage.  

2. Fighter/Rogue

This is a truly excellent multiclass, embodying the martial prowess of a fighter with the stealth and cunning of a rogue. Their different abilities work well together in surprising ways, and it offers a chance to create a different kind of fighter, with more intelligence and sneakiness than the usual stereotype.  

Why Fighter/Rogue Is Great 

• You only need to take about two or three levels in rogue to experience a major power up through Expertise, Sneak Attack, and Cunning Action. 
• Expertise doubles your proficiency bonus for either two of your skill proficiencies OR for one and your proficiency with thieves' tools. This is always good, and it's recommended that one of these proficiencies is in Athletics. 
• You gain Cunning Action after dipping into two levels of rogue, which allows you to dash, disengage, or hide as a bonus action. This makes your fighter more mobile, able to jump in and out of combat as they wish. 
• At level three of the Assassin archetype, you gain the Assassinate ability. You get advantage on attack rolls against creatures that haven't taken a turn yet in combat, and this feature guarantees critical hits for any enemy you have surprised. This is amazing in combination with the Action Surge feature of fighters. 

1. Fighter/Barbarian

This multiclass is the ultimate physical combatant, combining the best qualities of both to make a potent melee warrior. If you’re looking to inflict mass amounts of physical damage through pure strength and expert command of your weapons, this is the way to go. 

The fighter and barbarian classes are incredibly synergetic with each other. Both focus on making the most of their physical abilities on the battlefield, and pretty much anything in the lower levels of barbarian is useful to the fighter. While I prefer the fighter/rogue combination for roleplaying purposes, this multiclass just makes a lot of sense. 

Why Fighter/Barbarian Is Great

• Dipping into barbarian gives a fighter Rage, which is a huge boon for them. This gives you advantage on Strength checks and saving throws, increases the amount of melee damage you inflict, and gives resistance to bludgeoning, piercing, and slashing damage. While you cannot rage in heavy armor, the trade off is worth it. 
• Gaining a second level in barbarian provides you with even more opportunities to gain advantage. There’s Reckless Attack, which gives you advantage on all Strength melee weapon attacks, and Danger Sense, which gives advantage on Dexterity saving throws against visible attacks.
• I’d encourage choosing the Champion archetype, since the increased chance of a critical hit doubles when you have advantage. 
• Overall, this multiclass gives more damage output and resistance to damage, more opportunities for advantage and critical hits, and marginally more hit points. All of the abilities you gain from the barbarian class work well with the fighter's abilities, especially Action Surge. A fighter/barbarian is guaranteed to be one of the most ferocious melee combatants in the game. 

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