Bonded Companion

At 1st level, depending on what kind of bond you take, you will gain a companion, that will serve and aid you in every way possibly can.

The companion gets some bonuses from being linked to you. In combat, the companion moves and acts on your initiative. You can tell it what to do verbally (no action needed), and if you're incapacitated, it will do its best to protect you and itself. You are in control of your companions actions, and controlling two souls can be difficult, on your turn only one of either you or your companion can take the 'Attack' action, you can't both take it.

It gains proficiency in two skills of your choice. In areas where it would use its proficiency bonus, it uses your proficiency bonus instead. It also adds your proficiency bonus to its AC. Your companion will always use Strength for it's attack rolls and damage (unless otherwise specified), and it's damage dice is shown in the 'Companion Damage Dice' table on the Soul Binder feature list and it will grow when you gain more levels in this class. If a feature for you or your companion requires another creature to make a saving throw your Soul Binder save DC is equal to 8 + proficiency modifier + Charisma modifier.

If your companion is reduced to 0 HP, it falls unconscious and makes death saving throws just like a player would. When it is reduced to 0 HP, the soul binder will take any excess damage from the attack that reduced your companion to 0 HP (Example: if the companion has 10 hit points and takes 20 damage, the soul binder will take 10 damage). If it is killed, you can return it to life over the course of a long rest. The process of reviving can be very hard for your soul, and you gain one level of exhaustion at the end of the rest when you revive your companion. The companion will have its own hit die, and can spend them during a short rest.

Whenever you gain the Ability Score Improvement class feature, your companion’s abilities also improve. Your companion can increase one ability score of your choice by 2, or it can increase two ability scores of your choice by 1. As normal, your companion can’t increase an ability score above 20 using this feature unless its description specifies otherwise. Whenever you gain a level in this class, your companion also levels up, and it can increase its hit point with its hit die, like a players does. At first level, its hit points will be equal to the maximum value of its hit die + its Constitution modifier.