The Marrow Mage

as a sub school of necromancy the marrow mage focuses more strengthening one’s self through manipulating skeletal structures to create protection as well as tampering with skeletal undead, making them a force to be feared.

A marrow mage fuses together necromancy with abjuration magic to create armour using the marrow of skeletons and even creating greater undead, fusing them with protective magic.

Marrow

Starting at 2 level, you have learn how to extract the bone marrow within creatures, using the necromantic essence from within to use for yourself, trapping it within yourself. You have a number of Marrow points equal to 1+ your intelligence modifier that you can spend to do different action. You can regain marrow from using Bonecraft as well as when you take a long rest you regain 1 marrow.
you can only regenerate all your marrow points once a day. you must take a long rest to have this reset.
You can spend your marrow points to activate different ability’s you can only chose 2 at a time to have activated. When you take a level up you can switch out the ability’s to a different one. These ability’s being:

Bone minion

As an action you can spend up to 2 morrow points to animate a skeleton body within 20 feet of you. The Bone minion listens to your every command and they are friendly to you and your allies they go after you in initiative. You can equip your minion with weapons and armour you can only have one bone minion at a time. The skeletal minion stats are listed below

Once you reach level 10 you can have 2 minions at a time.

 

Bone minion 

Medium, undead 

Armor Class 12

Hit Points  (the casters proficiency bonus X the casters intelligence modifier) 

Speed 30 ft 

Immunities. necrotic, poison
Venerability’s. Bludgeoning, thunder, force
condition immunities. Poisoned, exhaustion
Senses darkvision 60 ft., passive Perception 10
Languages understands the languages you speak but can't speak them

Actions

Melee weapon attack. Melee Weapon Attack: + 2 + (your spell casting intelligence modifier) to hit, reach 5 ft., one target. Hit: weapon damage dice + 2 + casters intelligence modifier.

Blastbone (on death). on death once the bone minion has died any target within 5 feet of the minion must make a dexterity save DC (8+ casters intelligence modifier) or suffer 1d8 necrotic damage. Half on a save.

 

Disdain Harm

As a reaction you spend 1 marrow point to reduce any damage that is not bludgeoning, poison, force or psychic damage by 1d8. You can add a additional d8 to the pool for every marrow you spend on top of that.

Health Avarice

Health Avarice. As an action you can spend 1 marrow point to give a creature or undead you touch 2d6 temporary hit points. Any undead creature effected by this gains an additional 5 temporary hit points.

Mortem sight

As a bonus action you can spend 1 marrow point to gain darkvison for 60 feet for the next hour. You can also see a faint grey outline of any undead within the radius. You can see them through walls.  

Necrosis resistance

As a reaction can spend 1 marrow point to gain resistance to necrotic, slashing, pircing and cold damage but you become vulnerable to bludgeoning, fire, force and thunder damage until the beginning of your next turn.

Bonecraft

Starting level 2, a marrow mage learns how bone structures work, how to tend to body’s to extract them and to manipulate using necromancy to craft and creature.
A Marrow Mage can spend some time with a set of bone to manipulate them, this can be done in different ways as well as taking different amount of time to do so. These being:

Extract marrow. you can spend 1 minute you can touch a dead creature that has a skeletal structure and gain 1 Marrow. You cannot do this to the same body more than once and if the body has died within the last 10 minute.

Strip to the bone. You can spend 1 hour within a body stripping the skin, flesh and muscle from it leaving behind the skeleton.

Bone weaponry. By infusing bones, moulding them and combining them you can create some basic weaponry. Spending 15 minutes with a set of bones you can create any simple melee weapon.
Once you reach level 10, you can create any martial melee weapon.

Bone armour. By infusing bones, moulding them and combining them you can create basic armour for yourself. You can spend 1 marrow to create peace mail bone armour. You gain +1 to your AC for the next hour. This armour can be broken with bludgeoning damage.
 Once you reach level 10, you gain +2 to your AC.

Mantle of the undead

Through trial and error you have crafted using the rib cage, spinal cord and gemstones creating this bone mantle that rests on your back. At level 6 you are able to craft this mantle. Spending 5 hours and 300gp worth of materials to create.

While you have this mantel, you gain a aura of 20 feet. While you have skeleton's within the aura you can spend 1 marrow point to add 1d8 to there damage for there next hit or you can add it to their roll to hit.
as an action you can spend a spell slots of 2 level or higher to invigorate one your undead within the aura granting them a extra attack. Adding a extra level will allow you to target a additional undead.

The mantle can be destroyed when targeted or with an area of effect spell. The mantle has a AC of 14 and hit point equal to you wizard level X2. It has resistance to cold, slashing, pircing, fire, necrotic and lightning but is vulnerable to bludgeoning, force and thunder damage.

Aspect of death

while delving in to manipulation of bonecraft you have discovered a way to make yourself more in tuned with life after death, undead thinking you are one of them. once you have reach 10 level, undead ignore your presence making it some you can walk on by. Any undead that has a challenge rating of 3 or lower must make a wisdom save, on a fail the undead cant target you or see you.

Marrow Tyrant

Mastering the art of extracting the necrotic energy’s of the deceased, overpowering yourself. Once you have hit 14th level when you gain marrow points you gain an additional 1. You can also go over your max marrow points up to a max equal to your proficiency bonus for the next hour. If you have spent the points then they will disappear.