Assassin is a servant summoned in the Broken Apple Grail War, in New York City.
His true identity is Cain, the first murderer from the biblical stories, after killing his brother Abel, he was cursed to wander The World and never rest, unable to die. Many legends were made about him including some where he was a vampire, those where he murdered more after Abel etc. These were all added to his legend and recorded in his saint graph, regardless of validity, making him into something beyond what he was as the first killer.
Tier: 6-C. Higher with Natural Body. Varies, up to Low 1-C, possibly 1-C with Sevenfold Vengeance.
Name: Assassin, Cain, Murderer
Origin: The VS Wiki Holy Grail War
Classification: Servant, Heroic Spirit, Assassin-class Servant, Anti Hero, Dead Apostle
Powers and Abilities: Superhuman Physical Characteristics, Skilled Hand to Hand combatant and Knife User, Immortality (Types 1, 2, 3, and 7), Invisibility and Stealth Mastery with Presence Concealment (Presence Concealment users with B-rank or higher are capable of rendering themselves invisible by erasing their presence, making themselves difficult to detect against Magi and even Servants unless they attack), Magecraft, Curse Manipulation, Conceptual Manipulation and Durability Negation with the First Killer (Cain removes the concept of murder and death from the world making it so no human will perceive his attack as harmful, his knife also conceptually imposes the same wounds and damage that Abel had incurred, putting those who are hit in the same near death state that Abel was in during his last moments), Corruption and Soul Manipulation (A bite from a Dead Apostle not only corrupts the body, turning it into a vampire, but also corrupts someone's very soul, polluting their being), Telepathy, Invulnerability through Attack Reflection and Damage Amplification (With Sevenfold Vengeance), Regeneration (Works by reversing time; At least Mid, likely High-Mid normally; his regeneration should be comparable to that which Roa gains under the full moon. Low-Godly over time / with lots of energy), Memory Manipulation and Mind Manipulation with Mystic Eyes of Enchantment (looking into his eyes, or upon his body can charm someone, allowing him to change their memories as or make "suggestions" which they will follow), Servant Physiology
Attack Potency: Island level (As a servant with A+ rank strength, Cain should be comparable to Sakata Kintoki and Heracles). Higher with Natural Body (Can temporarily rank up his Strength stat, making him stronger than he normally is). Varies, up to Low Complex Multiverse level, possibly Complex Multiverse level with Sevenfold Vengeance (Attacks reflected by his Noble Phantasm are conceptually boosted to 7x strength, via the Authority of God, working on attacks of any magnitude so long as they do not surpass the Authority of God), Negates durability with The First Killer.
Speed: Massively Hypersonic (Possesses an agility stat of B, making him comparable to some of the faster Servants).
Lifting Strength: Class 25 (Should be comparable to F/SN Saber).
Striking Strength: Island Class, Higher with Natural Body.
Durability: At least Island level physically, Low Complex Multiverse level, possibly Complex Multiverse level with Sevenfold Vengeance (Cain possesses EX rank endurance and as such should be far superior to servants possessing A rank endurance in addition his Noble Phantasm prevents most attacks from harming him, reflecting them via Authority and remaining unharmed).
Stamina: High, likely Limitless (Possessing A rank Independent Action and being a Dead Apostle, he should likely have superior stamina to most servants, on-par with Dead Apostles, he was cursed by God to never stop wandering for as long as he lived, and was also cursed with immortality).
Range: Extended melee range, Unknown with Sevenfold Vengeance (It seems to be able to reflect damage onto the attacker regardless of their position).
Standard Equipment: His Knife
Intelligence: Cain has an extensive knowledge of murder due to his status as the first killer and he gained a good bit of knowledge during the time he walked the Earth. He is instinctively aware of many methods of killing his target, even those methods that would been devised seemingly after his time due to his immortality. In terms of killing knowledge, he is on par with the likes of Angra Mainyu when it comes to killing humans. Besides topics of murder, Cain had accrued a vast amount of knowledge on various fields during his time wandering, although he never managed to take the time to master any as he was never able to stop wandering.
Weaknesses: Looking upon his mark will let the target know his identity, his Presence Concealment and Endurance rank down in the sunlight, Servants of God don't take as much damage from their own attacks, weapons with an anti divinity effect, due to their ability to slay gods, are able to somewhat bypass this although they can't avoid the effect entirely, being able to hurt him, but still taking some reduced damage as a result.
Note: Cain does not possess Low 1-C, possibly 1-C durability, his ability works on attacks up to a Low 1-C, possibly 1-C level, deflecting them in order to negate harm via Authority. If an attack is able to bypass that Authority, it can hurt him as normal due to the fact that his actual durability is only 6-C.
Notable Attacks and Techniques:
God's Mark: Cain is cursed with immortality due to killing his brother and will never die of disease, poison, or age and can recover from wounds that he manages to take. Any who glance upon the mark, which is on his chest which he always attempts to hide, will know his identity and sin, learning his noble phantasms and skills in the process.
Sevenfold Vengeance: Any who attempt to slay Cain are punished by the lord with vengeance sevenfold, dealing damage seven times as great as what Cain would have taken. This noble phantasm is limited in that things that do not actually harm Cain in a literal sense can still affect him with no drawbacks. In addition a servant of God takes less damage from attacking Cain. Weapons with an anti divinity effect, due to their ability to slay gods, are able to somewhat bypass this although they can't avoid the effect entirely.
The First Killer: As the first to ever kill, Cain performed an action unknown to all previously. Due to this no one is able to notice his intent to kill, all humans are stripped of their knowledge of murder and death and will not attempt to protect themselves from his strike as the concept of murder is expunged from The World. Non-humans are not affected by the removal of the knowledge as beasts had been hunted and killed prior to Cain's sin. His strike is impossible to avoid or defend against for humans, partially due to them not knowing they need to and partially due to the nature of the attack. Upon Cain's blade touching the target they are instantly inflicted with the same injuries that Abel was, even if the blade doesn't damage them. It is possible to survive and recover from these wounds if one acts fast enough however humans would still not be fully aware of the fact they need to do this. Any non-humans of course would still register the danger of the strike and try to avoid it, although it still pierces defenses by inflicting the same lethal wounds Abel had.
Presence Concealment: Cain wasn't extremely stealthy when he committed his crime although the fact he did this without his goal being known was enough for him to earn this rank of presence concealment, in the sun it is ranked down due to his aversion to light, giving him a C+ rank in Light and a B rank otherwise.
Independent Action: Due to wandering non stop in many tellings of his legend, Cain has obtained the ability to act for extremely prolonged periods of time without mana support from a master.
Divinity: In some stories, he is born of Eve and Lucifer, a child of the flesh and spirit, inheriting the former divine spark of the angel Samael.
Nature of a Rebellious Spirit: After rebelling by killing his brother due to greed, he was cursed by God to never stop wandering and he gained this skill at a C rank.
Natural Body: As the firstborn son of Adam and Eve, the first humans, he possesses a perfect body free from any degradation or decay, in addition, his immortality prevents his body from deteriorating over time due to this he has an EX rank.
Innocent Monster: In some versions of the legend, Cain is portrayed as the first vampire, and he has been modified accordingly, gaining some properties of a vampire such as a slight aversion to sunlight, weakening his presence concealment and endurance while in direct sunlight, while also giving him the powers of a Dead Apostle. In some stories, he is the fruit of union between Eve and Satan, granting him properties from that as well giving him a C rank in this ability.
Manslayer: As the first killer Cain has a great advantage when fighting any of human origin due to this skill.
Bloodsucker: Cain is able to consume blood to restore his own vitality and mana, those he bites are also turned into vampires which can be brought under his control.
Mystic Eyes: He has gained Mystic Eyes of Enchantment due to becoming a vampire, allowing him to control the minds of those who look into his eyes and charming those who look upon his body or into his eyes.