[quote="RubyAndOnyx, post:1, topic:346876"]
As I understand it, Catholicism says that dying as a martyr acts as a "baptism of blood" for the unbaptized, and they are considered to have been baptized at the instant of their death and thus cleared of all sins.
Do martyrs need to die for their own faith, though? Would a non-Christian who sacrifices his or her self to defend Christians from persecution count as a martyr and thus receive a baptism of blood? Additionally, does self-sacrifice with no religious motivation have any inherent redemptive qualities?
As was previously said, we do not know all that God considers in determining an individual's salvation outside of Baptism. However, it is reasonable to believe that a person who is perhaps not of any particular theology at all and who has never had the opportunity to be Baptized but who lives according to the inherent principles of morality instilled in us by God and who under such circumstances selflessly sacrifices his or her own life in an attempt to help others, could reach salvation, but that is not Baptism by blood.
In order for there to be "Baptism by Blood", the death must have been for the sake of the faith without yet having had the opportunity to have been Baptised and are then baptized by their death for and with Christ.
As far as Baptism and Baptism by Blood, see the following from the Catechism of the Catholic Church:
1257 The Lord himself affirms that Baptism is necessary for salvation. He also commands his disciples to proclaim the Gospel to all nations and to baptize them. Baptism is necessary for salvation for those to whom the Gospel has been proclaimed and who have had the possibility of asking for this sacrament. The Church does not know of any means other than Baptism that assures entry into eternal beatitude; this is why she takes care not to neglect the mission she has received from the Lord to see that all who can be baptized are "reborn of water and the Spirit." God has bound salvation to the sacrament of Baptism, but he himself is not bound by his sacraments.
1258 The Church has always held the firm conviction that those who suffer death for the sake of the faith without having received Baptism are baptized by their death for and with Christ. This Baptism of blood, like the desire for Baptism, brings about the fruits of Baptism without being a sacrament.
1259 For catechumens who die before their Baptism, their explicit desire to receive it, together with repentance for their sins, and charity, assures them the salvation that they were not able to receive through the sacrament.
1260 "Since Christ died for all, and since all men are in fact called to one and the same destiny, which is divine, we must hold that the Holy Spirit offers to all the possibility of being made partakers, in a way known to God, of the Paschal mystery." Every man who is ignorant of the Gospel of Christ and of his Church, but seeks the truth and does the will of God in accordance with his understanding of it, can be saved. It may be supposed that such persons would have desired Baptism explicitly if they had known its necessity.