Dhampir's Champion

Some warriors do not find their strength alone to be sufficient enough to combat the evils they face. Through a dark ritual, certain aspects of a vampire can be emulated by those with the strongest of wills. The effects of the ritual manifest in a dark energy that empowers their body and allows them to absorb the life force of other creatures. These knights are not vampires in a real sense--they are perfectly capable of entering houses uninvited, standing in sunlight, or eating garlic. They merely trade some of their blood for darker blood in a ritual that benefits both their vampire patron and themselves. Many vampire knights will never know their patrons, but some actively seek them out. However, even without some weaknesses, the pain still lingers as sunlight can eventually pierce the skins of themselves. 

Spellcasting

At 3rd level,  you gain wizard spellcasting abilities as the knowledge-hungry vampires give lust for knowledge.

Dhampir Lineage

The dhampir still holds the powers from its other half-vampire family. Holding onto this, the Dhampir even if wanted cannot release this lineage, as this is known as the curse of birth. The powers the dhampir has widens as they grow old, but as they grow old the same with the weaknesses. Your weapon attacks score a critical hit on a roll of 19 or 20. The following strengths are given and can evolve at later levels:

• Supernatural perception for supernatural creatures (Natural Sense for Werewolves)
• Regeneration (Heals 1 vampire dice every hour)
• Immortal Age (Immortality)
• Sunlight Sensitivity (Glitters in the sun, but not instant death)
• Animal Speech and Control (Natural speech to animals and advantages on animal handling)

At level 3 these skills are basic and draining, costing either small sacrifices or personal health. Your vampire dice is how draining it costs. The abilities scale from levels 3,7,11,14, and 18, but these skills can still be effective. The higher the level the better the sense can be. All of this is determined by the GM 

Vampire Dice: Levels 3(1d6) 7(1d8) 11(1d10) 14(1d12) 18(1d20). With more sacrifices and even later age, the Dhampir doesn't use the vampire dice any longer.

Intense Enhancment

You gain the ability to use your enhancements to fuel your power. This power can be something as small as taking 1 damage from your vampire dice to using your own life. This intense enhancement calls for sacrifice, either of your own, or of someone elses.

Vampire Fighting Style

At 10th level, You can choose a second option from the Fighting Style class feature, or you gain the ability to use your vampiric fangs to bite into someone's neck as a reaction. 

Archery

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.

Dueling

When you are wielding a melee weapon in one hand and no other weapons, you gain a +2 bonus to damage rolls with that weapon.

Great Weapon Fighting

When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2. The weapon must have the two-handed or versatile property for you to gain this benefit.

Protection

When a creature you can see attacks a target other than you that is within 5 feet of you, you can use your reaction to impose disadvantage on the attack roll. You must be wielding a shield.

Two-Weapon Fighting

When you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack.

Vampire's Knowledge

After waiting for someone to strike, you can use your fangs to threaten someones life by biting down onto the enemy stealing health and dealing damages to them. 

Enhanced Battle Knowledge

After striking a critical hit, you are able to a creatures turn friendly or evil. After taking a turn the creature loses the turn they were placed on.

The Curse at Birth

At 18th level, at the start of each of your turns, you regain hit points equal to 5 + your Charisma modifier if you have no more than half of your hit points left. You don’t gain this benefit if you have 0 hit points. Also you gain near full abilities of a full-blooded vampire. Gaining the abilities to teleport 120 feet at will, extreme regeneration of 20 healing on your turn. Summoning bats and wolves, unless in a lair you gain full control to summon lesser vampires. Becoming almost as strong as a full vampire yourself if in a lair. The Dhampir's Champion become truly strong with strong abilities.

 

Summoning creatures is upon GM's choosing, however for an example you can use this template. 2d4 for bat based creatures, 1d4 for vampire spawn, 1d6 for dire wolves