Level 4: The Ever-Living Tank

I got the idea for this build looking at a warlock invocation in Xanathar's Guide to Everything called Gift of the Ever-Living Ones.

Gift of the Ever-living Ones
Prerequisite: Pact of the Chain Feature
Whenever you regain hit points while your familiar is within a 100 feet of you, treat any dice rolled to determine the hit points you regain as having rolled their maximum value for you.

This includes all healing that uses dice, like spells, hit dice from a short rest and class features that heals.

Race

As usual we will use a regular human for this build, here regular humans shine a little bit because they get bonifiers in many different abilities! Other races that are good for this are the ones that get a bonus to strength and constitution, dwarfs, half elfs, half orcs, etc.

Stats

For our stats we will use standard array. We will focus on Constitution and Strength, and then Charisma:

Str	Dex	Con	Int	Wis	Cha
15	9	16	11	13	14

Our high strength score will let us use Plated Armor in the future, and swing weapons like a pro. Our high constitution will help us get a high hp and our charisma will help with our spellcasting.

Progression

Our first level will be in fighter, we do this to start with chain armor, a shield and take the defense fighting style. All of this will make our AC a whopping 19, which is a lot! Here we will also get the Second Wind feature that lets us use our action to recover 1d10 plus our fighter level.

The next three levels will be taken in warlock. We will take the celestial patron and the Pact of the Chain in order to get access to the Gift of the Ever-Living Ones invocation. We absolutely need to take the Cure Wounds spell some moment along the way and we are done.

Result

A fantastic self healing tank. There's no other way to put it.

Lets start by basic tanks characteristics. Our build will have an AC of 19, (21 if they get plate armor) and assuming we take the expected value for our hitpoints they would have 37 hit points (12 from constitution, 10 for the first level in fighter and 15 for the three levels in warlock).

Lets talk first about the cure wounds spell first. With the invocation and the fact that we have level two spell slots this means that twice per short rest our character can recover 18 hit points (16 from the 2d8 and 2 from charisma). Or in other words HALF OF THEIR HP. Furthermore as an action they can recover 11 hit points because of second wind.

All of these features are recovered with just a short rest. But with just the hit die the build has they can recover a total of 46 hit points (12 from Con, 10 from fighter and 24 from warlock) in a short rest.

Furthermore Celestial Warlocks have the Healing Light feature, which means our build has a pool of 4d6 in this level from which they can expend two as an action to heal someone they can see within 60 feet. These dice restore themselves after a long rest, but basically let you heal yourself 12 more hitpoints per use.

Other extra features is that you can use your familiar to cast cure wounds from a distance. You can handle strength based martial weapons like battleaxes and war hammers (as long as you use them with one hand). The healing of most of these abilities increase with your level until level 10.