Nicholai was born and raised in London to a Russian mother and a British father. When London was destroyed by the Nazi vampires and the Crusaders, he was attending college in America. After hearing of the attack, he dropped out and caught a plane to London in hopes his family survived. He had to take a plane to wales and hitchhike or walk the rest of the way. When he finally arrived in his old home town, it was in ruins. There was no sign of his parents or anyone but a few half dead people lining the streets. He turned to the Hellsing Organization. Having lost nearly their entire force and even Alucard, Integra was willing to accept anyone. One day, he saw Seras Victoria walking alone. He begged for her to turn him into a vampire so that he would no longer feel weak and useless. Seras was suprised to see him so distraught for someone who always seemed upbeat and eager. Seras, having felt similar at a time herself, made Nicholai into her first fletchling.
Most of the time, Nicholai is very childish, vulgar, or outright immature. The only times he is shown to be serious is when he thinks about his parents. He is known to joke around out and in fights. He taunts his opponents. He enjoys fighting and will often make fights or get angry if his opponent quits. He often annoys Integra with his childish acts and stubbornness. Occasionally, Seras regrets making him into a Vampire. The first person he drank blood from was a vampire he and Seras were sent to kill. He showed no hesitation, much to Seras' surprise.
Due to having highly advanced senses, Nicholai is very good shot and carries many guns with him.
He carries three on each side of his abdomen, one on each of his thighs, and eight on the front of his abdomen. The guns vary in Caliber and ammunition type.
The three on his left along with the two on the left side of his stomach use 45.ACP armor piercing rounds. These are meant for long range engagements and armored targets.
The three on his right side along with the the two on the right side of his stomach use the same Caliber but Hollow Point rounds. These are meant to be used on unarmored targets as AP rounds will pass through some with minimal internal injury. Hollow point rounds shatter and cause a lot of internal damage like shrapnel from a grenade.
The two on his thighs and are 9mm, one Armor Piercing, the other hollow point. They are meant for close range engagements where the larger guns would be a handicap.
The two on his chest are 13mm and specially designed for him by the Hellsing organization. They shoot silver bullets with explosive tips. These are the guns he uses againts vampires or other superhuman targets.
After feeling that the 13mms weren't getting the job done, Nicholai constructed 2 specially made .50cal hand cannons. They Fire .50cal silver bullets with explosive shells and mercury tips. These bullets are almost double the size of the 13mm he used to use.
Being a vampire, Nicholai's strength is supremely impressive. Being able to shatter a wall with a smack of his hand crush through buildings with a dive of his body. His strength has been shown to be able to lift up many high objects.
Nicholai is immortal and cannot be killed by normal means. This allows him to receive fatal injuries that would normally kill people regardless of if they had powers or not. This also allows him to be killed many times from all the souls he has taken from blood sucking.
Klaus can be completely obliterated and reform from completely darkness and shadows. Nicholai's regeneration allows him to reform from darkness. For example, he has been burned to nothing but ashes (by himself when he was bored) and regenerated like nothing happened.
Being a vampire; a person that Nicholai bites and doesn't suck blood from becomes a Fledgling. With a person being a fledgling, they now have a connection to Nicholai and he is able to telepathically speak to them, as stated before. This means he can give them orders and teach them, even having them fight for him. This allows Nicholai to have people under his control, since they now respect him as their leader.
People who Nicholai drained all blood from can be summoned at anytime as mindless familiars. Current Familiars include: 2 spies. About 35 Gula Soldiers. 30 Survey Corps soldiers. About 50 marines and a Vampric Marine Captain. A shitload of people he ate during his walks and throughout jis very long life.
Nicholai can change his physical appearance at will.
Nicholai made a blood contract with the demon Mammon.
While using his seal he gains the ability to manipulate fire. He uses it to launch power fire attacks at his opponents, or to make his bullets even more deadly.
Knight of HonorEdit
This is an ability possessed by Nicholai, that allows him to pick up almost any object, and turn it into an incredibly powerful weapon. For example, he can pick up a mere stick, use Knight of Honor to enhance it with his mana, and then use it to combat a legendary weapon such as Excalibur or Ea, on an even level. As said, this can be used on almost any object, unless the object is already a very strong weapon. For example, he would be unable to enhance a weapon such as Excalibur, as it is already incredibly strong. However, Knight of Honor would allow him to use Excalibur effectively, even if he himself isn't the owner. It also allows him to basically steal the Noble Phantasms of Servants, and have them become weapons of his own. This is permanent, unless the servant manages to take it back from him. No one else but the servant itself would be able to take it from him however.
It was revealed that Jenkins was merely a split personality formed by Nicholai out of the denial of losing his vampirism. After being bitten yet again by a vampire and changing once more, Nicholai retained his old memories. He can use all abilities listed on the page of Jenkins.