Inhuman Fighter (Shield)

You were built to defend others, either by laying down your body for them or obliterating your enemies before they could inflict harm. In simple, undeniable words, you are a SHIELD. So defend as many as you need to, and USE whatever means you have too.

Intellectual Might

Your mind and instincts were bred to be one of your greatest strengths. Thinking your way out of bad situations is one of your key points, along with cases of pure brute force and mobility as you gain improvements based on your intelligence. 

• When you roll Athletics, Acrobatics, or Survival, you can add your Intelligence modifier to the roll.
• Your Unarmed Strike becomes a 1d12 based on your Intelligence modifier. The damage die will increase at 6th level and again at 12th level.
• You gain movement speed equal to half of your Intelligence modifier..
• Whenever you are within 5ft of a ally creature, if they are attacked, you can automatically take the attack or save thrown at them if you can respond to it without expending a action (DM's discretion).
• When you attack with a unarmed strike, you can decide if the damage dealt is either piercing, slashing, or bludgeoning damage.

At the start of combat, you may gain temporary hitpoints equal to your Intelligence modifier times 10. You can use this feature equal to your proficiency modifier.

Heightened Procedures

Your ability to both move and think quickly allows to you support yourself and protected units. When you or another creature you can see within 30 feet of you makes an ability check, or a saving throw, you can use your reaction to add your Intelligence modifier to the roll. As a bonus action as well, you can use this feature to add to one creature(other than yourself) attack rolls or damage rolls until the end of their turn.

You can use this feature a number of times equal to your Intelligence modifier (minimum of once). You regain all expended uses when you finish a long rest

Battle Tactics (Perfect-C)

While you are a suitable frontal shield, you may be lacking in terms of direct attacks....however, your ability to take a blow and react with a even stronger attack is outstanding. When another creature attacks you physically (ranged or melee) or makes you attempt a physical save, you can attempt to make a attack against that creature if they are within range (DM's discretion) at advantage, without requiring a reaction. If you hit your attack, you can expend a reaction to deal extra damage equal to your Intelligence modifier times 3. When you deal damage this way, you will gain temporary hitpoints equal to the damage result.

Invincible Shield

As your experience, battle skills, and your body grow, your ability to defend your allies from any sort of danger and live afterwards has made you something close to invincible. At the start of combat, you will gain temporary hitpoints equal to your constitution modifier times 10 (stacks with Intelligent Might). 

Alongside the previous ability, as a action, you can gain roll (1d20) + (half of your constitution modifier times 10) and gain the result as temporary hitpoints. You can only use this feature once per round and only use this feature equal to your constitution modifier.

The End

At this point, you could be considered the most invincible thing alive. The being that could potentially survive the end of the world. While it might be a curse for others, for you? It lets you shield others from attacks flawlessly. 

As a bonus action, you can quite simply, become invincible to all attacks and saves for (1d10) days, unable to take damage. However, you become unable to attack and deal damage in return. And at the DM'S discretion, something out there is still able to kill you. 

You recharge this feature after whatever days you spent invincible.