<P> In season four, Elijah reappears as Katherine's lover, and is making a deal with Katherine for her to be granted her freedom from Klaus in exchange for the cure for immortality, which Klaus wants to give to Silas, the world's first and most dangerous immortal being, to avoid Silas' psychic torture . Elijah refuses Klaus the cure for Rebekah to take before Silas re-claims it, denying Katherine's freedom . Elijah breaks up with Katherine when he learns Klaus has fathered a child and returns to New Orleans to keep Klaus' unborn baby safe and help his brother . </P> <P> He follows his brother Klaus to New Orleans and finds out that Hayley is pregnant with Klaus' child . He begins to have feelings for Hayley and throughout' The Originals' the two make their feelings for each other clear . When Esther returns, she reveals the truth about how Elijah's first love, Tatia, was killed, proving it was in fact himself who had fed on her when they had newly been vampires . During one of Finn's spells Elijah is trapped in a room with animal heads which represent each brother of the family . To escape, Elijah discovers you must ruin the representation of each other, thus causing him to share with Klaus that he killed Tatia . When Klaus proves he is capable of forgiveness the spell is broken and they are free . </P> <P> Niklaus Mikaelson (more commonly called Klaus) is physically the most powerful immortal supernatural being in The Vampire Diaries and The Originals universe . He is shown to be cruel, sadistic, ruthless, and yet he finds love in Caroline Forbes . He's portrayed by British actor Joseph Morgan . After the Original couple moved to the Americas, Klaus's mother had an affair with a member of the neighboring werewolf tribe . Klaus was born as a result . The mother's infidelity was later revealed . His illegitimate birth as well as his perceived weaknesses made him the target of his step - father's ruthless hatred, emotional neglect, abuse, and contempt . </P> <P> When Esther turned the family into vampires, Klaus's blood - lust became particularly strong and he transitioned into a hybrid after his first kill, due to his werewolf gene . Esther later bound his werewolf powers to the moonstone, due to her believing that his hybrid status made him an abomination . In order to obtain his werewolf abilities, Klaus had to perform a ritual in which a werewolf, a vampire and a Petrova doppelganger had to be sacrificed . Klaus first hunted Katerina Petrova, later known as Katherine Pierce, who was from the line of supernatural Petrova doppelgangers . In order to avoid being sacrificed by Klaus and allowing him to gain his werewolf powers, Katerina drinks the blood of a vampire and then kills herself in order to transition into a vampire . She then becomes useless to Klaus because his ritual requires a human doppelganger . Katherine subsequently spends centuries on the run from Klaus, who is enraged at her actions . As a result, Klaus kills her entire family and continues to hunt her obsessively . </P>

What is the age order of the originals