Captian Tactical 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.

Stalker. At level 3 you've chosen to stay in the scout company of your chapter, You gain proficiency with light armor and Stealth

I've seen this before. At level 15 You've learned to trust nothing at a first glance, As a bonus action you can choose to prone yourself and as an action go on overwatch which lets you take an attack opportunity using a ranged weapon, while you're prone your sight range is increased to 120 ft and your passive perception gains +10.

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.

Rapid deployment. At level 16 As an action you can dash toward an enemy while taking an attack action every attack is made with disadvantage

Brother's in Arms. 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

Never saw it coming. At level 18 You've become one of if not the best scout in the company and as recognition you've gained access to stealth field tech and your metla bombs have been replaced with Satchel charges which do 6d8 fire and triple damage to structures and objects the stealth field grants you effects of a ring of invisibility

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

Combat Knife. Melee Weapon Attack: +15 to hit, reach 20 ft., 1 target. Hit: 24 (5d6 + 8) Slashing damage. 

Bolter. RangedWeapon Attack: +15 to hit, range 160/480 ft., 1 target. Hit:  57 (8d12 + 8) Piercing damage.

Burst Fire. The space marine sprays a 20-foot cube area within 160 feet of him with shots from his bolter. All creatures in that area must make a DC 20 Dexterity saving throw, taking 25 (4d12) piercing damage and 37 (6d12) slashing damage on a failed save. This uses up 10 pieces of ammunition.

Blinding flash. At level 5 you gain 3 charges of flash bangs these grenades have a radius of 30ft and as an action can be thrown 60ft creatures within the radius must a DC 15 Con save or be blinded and deafened for 1 minute.

Tools for the job. At level 10 You've proven yourself to your chapter and have been granted access to better equipment, You gain access to the stalker variant of the bolter and 3 melta bombs which 6d8 fire and deal triple damage to structures and objects, you gain all melta bombs back at the end of a long rest

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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