Is this balanced?

I make a lot of homebrew stuff, but i'm never really sure it's balanced.

Is this too powerful?:

3rd lvl: Heavy guardian

You gain 2 AC but lose 5 ft of movement speed while wearing heavy armour and carrying a shield. 

3rd lvl: Taunt

You can use a bonus action to taunt an enemy, forcing them to make a DC(8+CHA+PB) wisdom save. If they fail, they gain +2 damage for attacks but are forced to only target you, they can repeat this save at the end of each of their turns.

5th lvl: Body block

As a reaction when an ally becomes the target of an attack within ten feet of you, you can throw yourself into the blow, granting the enemy advantage and becoming the target of the attack. if the enemy misses, your ally can make an attack or cast a cantrip.

10th lvl: Adamantine body

You cannot be critically hit, and you have resistance to non magical bludgeoning, piercing, and slashing damage.

15th lvl: Ward

You designate an ally as a ward, While this ally is within 30 ft you can use body block As if they were five feet away, enemies gain disadvantage on your taunt, and you take half of all damage dealt instead of them.

18th lvl: Undying protector

You become immune to non magical damage and resistant to magical bludgeoning, piercing, and slashing dmg, you regenerate 1D6 hit points at the end of your turn for every time you've taken damage, You have advantage on death saves and treat an 18-20 as a 20, and your taunt save becomes a DC(10+Con+Cha+PB) Charisma save.

It doesn't look terribly unbalanced, some of it sounds neat. Is this for a fighter?

Quote from the_scalebrand >>

I make a lot of homebrew stuff, but i'm never really sure it's balanced.

 

 Try the homebrew forum

Yeah, I wanted a heavily armoured character, but all the best tank subclasses are for barbarian and they can't use heavy armour.

No, it is not balanced. For comparison, the Forge Domain Cleric only gets resistance to BPS damage at 17th level. Immunity to most damage dealt by monsters is insane, and will actually make you a worse tank, because no intelligent creature will attack something that's not taking any damage. Other than that, it seems fine. I'm not sure about Ward from a flavor standpoint. It feels oddly supernatural for an otherwise very nonmagical subclass.

Yeah this is pretty busted. 5ft move is a nothing penalty, you can just be something like an Air Genasi or cast Longstrider to beat it. Taunt is insane control, just spam it until they're locked onto you, same with Body Block. Adamantine is passive concentration-free Stoneskin. Ward teleports you I guess? And Undying Protector reads like a 5.0 ability, "non-magical damage" isn't a thing anymore.