Bloodhound

You’ve never had a humanoid friend you could rely upon. Lucky for you, you’ve got the best beast friend a body could ask for. Bloodhound Fighters are as faithful to their beast companions as their beast companions are to them.

Beast Whisperer

When you choose this archetype at 3rd level, you gain proficiency in the Animal Handling skill and double your proficiency bonus for it. 

Faithful Companion

At 3rd level, you gain a beast companion that accompanies you on your adventures and is trained to fight alongside you. Choose a beast that is no larger than Medium and that has a challenge rating of 1/4 or lower. Add your proficiency bonus to the beast’s AC, attack rolls, and damage rolls, as well as to any saving throws and skills it is proficient in. Its hit point maximum equals the hit point number in its stat block or four times your Fighter level, whichever is higher. Like any creature, it can spend Hit Dice during a short rest to regain hit points.

The beast obeys your commands as best as it can. It takes its turn on your initiative. On your turn, you can verbally command the beast where to move (no action required by you). You can use your bonus action to verbally command it to take the Attack, Dash, Disengage, or Help action. If you don't issue a command, the beast takes the Dodge action. Once you have the Extra Attack feature, you can make one weapon attack yourself when you command the beast to take the Attack action.

If you are incapacitated or absent, you can still control the beast on your turn. The beast never requires your command to use its reaction, such as when making an opportunity attack.

If the beast dies, you can obtain a new companion by spending 8 hours magically bonding with a beast that isn’t hostile to you and that meets the requirements.

Arcanine Bite

At 6th level, your beast’s attacks count as magical for the purpose of overcoming resistance and immunity to non-magical attacks and damage.

Coordinated Attack

Also at 7th level, you and your beast companion form a more potent fighting team. When you use the Attack action on your turn, if your beast can see you, it can use its reaction to make a melee attack.

Beastial Fury

Starting at 11th level, when you command your beast companion to take the Attack action, the beast can make two attacks, or it can take the Multiattack action if it has that action.

Blood Brothers

At 11th level, when a creature deals damage to your beast with an attack, you can use your reaction to make an opportunity attack against that creature if you are within range.

One with the beast

Any positive buff or effect cast on either you or your beast effects the other. This applies to effects such as potions, spells and even magical items. The effect must be a sustained or instantaneous effect (such as a cure wounds spell) and does not apply to permanent passive bonuses (such as the attribute bonus from an Ioun stone).