Captain Libarian space marine

Brave. The space marine is immune to the frightened condition 

Keen Senses. The space marine has advantage on Wisdom (Perception) checks that rely on sight, hearing, or smell

Martial Advantage. Once per turn, the space marine can deal an extra 11 (2d10) damage to a creature it hits with a weapon attack if that creature is within 5 feet of an ally of the space marine that isn't incapacitated.

Regeneration. The space marine recovers 15 hit points at the start of each of its turns as long as it has at least 1 hit point remaining.

Superhuman Biology. The space marine is immune to poison, nonmagical diseases, and the effects of exposure to extreme heat and extreme cold.

Insulated. The space marine has advantage on saving throws against the effects of exposure to extreme heat and extreme cold.

Fighting Style. As an Astarte's you're trained in most types of prevalent combat, but You've picked a favored style of combat, You gain 1 Fighting style at lvl 3, another at 9 ( Marksmanship You gain a +2 bonus to attack rolls you make with ranged weapons. Defense While you are wearing armor, you gain a +1 bonus to AC. Fortified build You gain advantage against any effects which would displace you or effects that would make you go prone.)

Carry A Big Gun.  At level 2 you've been trained so that your reloads are basically done in nanoseconds, you ignore the reload property on ranged weapons except for weapons' with the heavy property, They instead use a bonus action to reload. Bolters and bolt pistol's do not have the heavy property nor do bolter's have the two-handed property when you wield them.

PROMOTIONS. At level 10 you've been promoted to sergeant and can lead your squad to greatness. So long as an ally is within 25ft of you, they gain +1 to their attack rolls and advantage on their first attack roll in the combat encounter

Emperor's Fury. At Level 13 you've gained access to the rage of the emperor's finest. For 1 minute you gain advantage on all attacks, during an emperor's fury when you cause a creature to reach 0 hp you can execute the enemy and gain 13 temp hp. You can only use this ability once per long rest

Champion of Humanity: At level 14 You are the best defense against the uncaring world that leaves humanity wanting, you are their bulwark against the nightmares and the foul beings of an uncaring world and you shall hold, When you reach half health you can as an action inspire your allies giving them a d12 inspiration die which only be used in combat. you regain use of this ability after a long rest.

Fully Sealed. While wearing the helmet, and there are no holes in the armor, you can breathe as if you always have air.

Night Vision. While wearing the helmet, you have darkvision out to 60 feet.

Life Support Systems. You are immune to extreme weather conditions and extreme heat and cold.

Servo Motors. You count as one size larger when determining your carrying capacity and the weight you can push, drag, or lift.

Vox-Unit. the vox unit provides communication to any equipped with another vox unit in 4 miles.

Increased Protection. Thanks to innovations within design philosophy we are able to increase armor density and boot plating, you have resistance to bludgeoning, piercing, and slashing damage while wearing the armor.

Improved Rebreather. With new filtration technology we can ensure safety even in the most toxic or putrid environments, while wearing the helmet, you are immune to airborne poison or disease.

Pauldron Storage. The shoulders act as a rapid deployment system for ammunition. You can store up to 50 bolter rounds inside the pauldrons, and when you reload a weapon which uses them, you can use these rounds to reload the weapon without taking an action or bonus action.

Quickened Fire Bolt. The librarian may cast the fire bolt cantrip as a bonus action after making a melee weapon attack.

Chief Librarian At level 18 you've become the chief librarian of your chapter and have been gifted the right of keeping the relics of the chapter safe and secure. You gain one legendary item to protect with your life work with your DM to figure out what the weapon or item is and it's meaning to the chapter.

Spellcasting. The librarian is a 9th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 24, spell attack bonus +16). The librarian has the following wizard spells prepared, and may cast them without requiring material components:

Cantrips (at will): blade ward, fire bolt, mage hand, message
1st level (5 slots): detect magic, magic missile, shield, protection from evil and good
2nd level (4 slots): gust of wind, misty step, shatter
3rd level (4 slots): counterspell, lightning bolt, slow
4th level (4 slots): banishment, fire shield, storm sphere
5th level (2 slot): wall of force, cone of cold

At level 18 your Faith in your comrades pushes you and them into even greater heights of heroism, when you take an action your allies can follow your lead and when they do the same action they gain advantage on it. Affects allies within 30ft of you

Extra Attack: the space marine can attack 4 times twice with his unarmed combat knife twice or twice with his bolter and burst fire once

Combat Knife. Melee Weapon Attack: +13 to hit, reach 20 ft., 1 target. Hit: 18 (3d6 + 8) Slashing damage. 

Bolter. RangedWeapon Attack: +13 to hit, range 120/360 ft., 1 target. Hit:  79 (6d10 + 8) Piercing damage.

Burst Fire. The space marine sprays a 20-foot cube area within 120 feet of him with shots from his bolter. All creatures in that area must make a DC 15 Dexterity saving throw, taking 21 (4d10) piercing damage and 25 (4d12) slashing damage on a failed save. This uses up 10 pieces of ammunition.

Hold fast.  At level 6 you can as a bonus action take a knee and become 3/4 cover for your allies and this counts as you being behind 1/2 cover.

Parry. The unarmored space marine adds 4 to its AC against one melee attack that would hit it. To do so, the unarmored space marine must see the attacker and be wielding a melee weapon.

I've got your Back. At level 6 when behind cover or being engaged, as a reaction you can taunt enemies within 60ft of you, enemies must pass a DC 23 Intimidation to not be taunted, You gain AC bonus equal to the number of enemies taunted, you lose this bonus if you move positions. You can use this feature once per short rest. 

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