Lord Asriel is a major character in Philip Pullman’s His Dark Materials fantasy novels. His role is somewhat uncertain, as at times in the story he is treated as a protagonist, and at times as an antagonist, depending on Lyra’s feelings towards him.
Lord Asriel’s name is likely meant to evoke the name of the angel Asra’el, who is the Angel of Death in many Judeo-Christian traditions. Lord Asriel is also, in many ways, reminiscent of the rebel angel Lucifer.
Lord Asriel is presented as a brilliant, powerful aristocrat in Lyra’s universe. He seems to be respected and feared by even the most powerful beings in the many universes, and acts with a haughty sense of self-confidence and security in the rightness of his path. He is Lyra’s father, although he left her with the people at Jordan College in Oxford to look after her upbringing. He is also the lover of Mrs. Coulter, Lyra’s mother, although at the time the story opens they are estranged, and in fact appear to be working for very different factions.
Lord Asriel’s motivations always seem to be positive, and he views himself as a liberator of all of humanity and the other sentient races in the various universes. Although the means Lord Asriel uses to accomplish his goals, such as sacrificing a child to open a rift between worlds, are often of dubious morality, he sees these as necessary steps to accomplish a greater good. Everything Lord Asriel does is aimed at ultimately destroying the Authority that rules as God in the many universes, to create a Republic of Heaven on the various Earths.
Lord Asriel is a very intelligent man, who specializes in what is termed experimental theology in Lyra’s world. This seems to be roughly analogous to various branches of physics in our world. Lord Asriel is particularly interested in Dust, and the other worlds he sees through the aurora borealis while in the far north. He uses this knowledge to design a technique to breach the barriers between the worlds, a feat otherwise seemingly only accomplished by the subtle knife, by utilizing the immense energy released when a person is severed from their daemon.
Once through the rift into the nexus world of Cittagazze, Lord Asriel wastes no time in preparing to fight the Authority. He aligns himself with a rebel angel, Xaphania. He then begins recruiting powerful warriors from many different worlds, to wage a war even larger than the first war against Heaven. With Lyra’s help, Lord Asriel finally succeeds in destroying the Authority. Ultimately, he sacrifices his own life, as does his lover Mrs. Coulter, to destroy Metatron, the true power behind the Kingdom of Heaven, paving the way for the future Republic of Heaven he spent his life working towards.