Jews had their quota of martyrs and persecutors too, it is even recorded in the bible. They have an exclusive and identity-defining religion too.
You are asking about persecutions, or to any situation where people are willing to kill or die due to religion?
Aztecs and their human sacrifices of enemies and the eternal wars required to supply victims; Huron x Iroquois have some similarity, although many prisoners were kept as slaves.
Phoenicians killing their own babies as human sacrifices;
Canibalism in general, in many cases is quite religious;
Pagans in most of Europe, Central Asia, (or Hindus in India even in recent times) killing slaves/wives at the funeral of their masters/husband to follow them in afterlife, or as a offering to the gods for the soul of the master; Oh, Vikings would gang rape the slave girl first. The last one strangled the girl still in bed.
The famous roman case of the oracle which requested "an offering of the best thing belonging to Roma". Then the leader got his best armor and weapons and jumped down a cliff because the best thing in Rome was "Men and Arms", and he himself was the most badass of them all.
Chinese emperor building great tombs and them killing all the workers so that the tomb remains hidden and his soul rest is not disturbed in the afterworld. (similar with Gengis Khan). Alas, when the Chinese Emperor can get away with killing whole groups of people, it is not partially because he has the "mandate of heaven"? Most European kings would be considered total tyrants and risk deposition...
Japanese commiting seppuku at command from the emperor, or just due to honor issues, which is partly religious.
Vestal Virgins which were killed if found to be not virgins anymore.
Aztecs also had a special offering of a young man from one of their ruling families. He had one year of 'paradise' with the best food and luxury and four ladies of his choosing (a coveted position). After that, he goes up the pyramid to have his heart taken... [A Cortes biography]
Some Brazilian native americans, had a kind of zodiac related to their gods, where people were assigned 'signs' related to the period when they were born. Some 'signs' were incompatible, and if a couple of incompatible signs would have sex or try to marry, both would be killed. [Gilberto Freire]
Caste violence in Hindu society is serious too. Killings and lesser attacks (like acid in the face of the low cast girl dating a high cast boy) still happens today. [see the news]
This without even start looking at muslim history, as you want BC stuff and not AD years, or at least civilizations not in close contact with christianity.
I wont also list many offenses not as serious as death, just some:
Greek/Roman oracles and taboos which changed their actions in strange ways, e.g. the Athenian generals which were punished (not sure if killed) after a great victory because they could not stop to fetch their dead floating in the water (big taboo letting corpses with no burial).
Some brazilian Tupi Indians, divided in tribes, they did not have much inter-tribe exchanges, but when they had a visitor from a related tribe, they would send their young girls to sleep with him as part of a religious welcome. Probably it was not so nice for the girl when the old fat Great-Uncle come to visit. [Freire or Sergio de Holanda]
So many people willing to be eunuchs in china.
Some of the examples above mix religion with political or societal issues, but is this not true also on any European religions conflict?
The point is that I do not think westerns are the only ones who take religion seriously enough.
And most of the examples above are serious violations of justice that were abolished with Christianity... Don't believe in Rousseau's "good savage"
But if you are asking why people are willing to die:
you would do anything at gun point?
Someone points a gun at your head, commands you, then you give money or information to a killer thug who will immediately harm other people; you help them to harm other people; you rape and kill your own family? No limits?
We may understand and forgive whoever folds and do whatever the thug wants, but the ones who did not fold were not the ones who did better, even heroically better?
If some people are willing to die before committing serious sin, aren't they right? If it is better (or heroic), not to betray your family even if you know they would forgive you anyway, then why it is ok to betray god?