Certain devil hunters will be given the opportunity if proven or forced onto them if they receive life threatening injuries to take on the heart of a devil becoming a hybrid no longer man nor devil while receiving the benefits and drawbacks of both. These individuals gain increased strength, movement, dexterity, and constitution along with nigh invulnerability as long as their heart is not completely destroyed or they run out of blood. They also gain physical properties of the devils they merge with when in their transformed state allowing them to use weapons that come from the body and a bite attack that regains health from the blood taken from the enemy. Although the drawbacks are costly as when transformed you gain disadvantage on all wisdom and intelligence checks along with saving throws. When transformed they also take on certain aspects of the devils personality causing massive mood swings and bloodlust at times and when reaching below half of the devil hunters hit points when transformed they must make a wisdom saving throw or attacking the nearest creature and can make the wisdom saving throw at the start of its turn.

Hybrid transformation

The devil hunter uses a bonus action to transform into a hybrid form allowing for increased abilities and actions along with taking on physical and mental characteristics of the devil. The devil Hunter must continue to form a bond with the devil to level up and become stronger.

Crossbow Devil

The Crossbow Devil is the calmest and least bloodlusted of the weapon devils but when in combat can get lost in the pleasure of fighting making it hard for the devil hunter to stop fighting even after receiving critical injuries. The Crossbow devil is also more inclined to be open to human-devil bonds allowing more of an symbiotic bond while still being new to the person they are bonded with. The Crossbow devil while bonded gives access to more mid to close range attacks due to its incredible speed and stealth making it an unique fighting style.Although once confronted it will not disengage unless something is critically wrong with the devil hunter.

Katana Devil

The Devil Hunter takes on the katana devil becoming a hybrid known for its incredible speed and immense destructive property while still being durable. The only downside physically is it's laziness as it is one of the fastest weapon devils but has above average distance traveled making it a monster in close encounter battles but struggles in longer range fights. The Katana devil is more of a creature of solitude not verbally interacting with even the Devil hunter it inhabits. Although once it warms up to its host the Katana devil becomes much more agreeable. The Katana devil often holds grudges that it will not let go until the person or devil that wronged it is dead or has made its amends and repaid its debt whether it be in blood, money, or servitude.

Longsword Devil

The Devil hunter has taken on the longsword devil allowing them access to two longswords that come from the hands that even a novice becomes a master when transformed with it being one of the more armored and durable devil hybrids. This is especially shown as it prefers to trade blows with enemies and has almost unmatched physical strength while still having impressive speed and agility. The Longsword devil craves combat along with bloodlust making the Devil Hunter much more inclined to seek strong enemies and to ignore the week. This Devil almost always acts first think later making the Devil Hunter incredibly confident when entering combat although it is definitely on the more exploitable side.

Spear Devil

The Devil Hunter takes on the spear devil a master of long range combat and close quarter encounters as the Spear devil can launch spears from its arms or wield them making it unique and incredibly versatile. Although it does deal with the drawbacks of being less durable then the other devils available making it an impressive asset in the right hands but quite the impediment if not utilized properly. 

semi perfect hybrid

Weapon devils are made from the weapons they represent allowing the user increased resistance from physical damage as they now have the iron like skin that the Devils inside of them originally had before becoming one with the Devil Hunter. The iron-like skin is only present when transformed and provides no protection from any non physical damage . Along with the improved armor the improved bond allows the Devil Hunter to use regenerative bite once more and recharges one charge every short rest and all charges being recharged after a long rest. The improved regenerative bite also deals increased damage and increased health points regained per bite.

Iron skin

Gain resistance when transformed to all physical damage as the devil hunter becomes physically and mentally more connected to the weapon devil allowing more of its physical features to be present and allows the devil hunter better control of its emotional outbursts no longer requiring disadvantage on wisdom saving throws when below half health

Regenerative bite

Devils can heal from critical injuries by feeding on blood and while not quite as strong the devil hunter can feed off of its enemies dealing damage and healing half of what it dealt allowing the hybrid to continue to fight even after receiving serious injuries. The bite can only be used twice before a long rest as the bond is not strong enough resulting in the body of the devil hunter regenerating much less than a devil would with the same amount of blood while also limiting the times they can consume blood before they're body begins to reject it.

Devilish instincts

when transformed the enhanced senses of the devil began to manifest now as the bond between the two continues to increase. This allows the hunter when transformed to attempt to parry an attack by rolling an attack with one of the natural weapons and if the roll matches then it is blocked and no damage is taken but if the roll is above then the attack is parried and opens the enemy for one attack and removes the chance for a second attack. If failed then the attack goes as normal taking the appropriate damage.