Crusade in the title Chrno Crusade doesn't seemed...
 

It doesn't seem to have much significance in the story other then like in one episode when they mention it... They should acctually expand more of the Crusade thingie...

Maybe they chose the word crusade just because of the diction and the fact that the "cr" sound matches that of the word "chrno".

or maybe because Crusade connotates a religious battle.. y'know, the Crusades?

I think they just made the title sound cool.

pfff what a ridiculous theory, mine is better.
...

:p

It could also just be "crusade" as in chrno's mission against evil. you know how like ppl "crusade" for a cause... It might even have been ambiguous on purpose to hold both meanings.

Hm...
Me thinkeths if you read the manga, you might feel that the use of the word 'Crusade' is somehow appropriate...
I guess it could be seen as either:

1.) Chrno's quest to seek what he wants (freedom/friendships/love, etc)
2.) Chrno acts like a crusader, accompanying Rosette on her quest of retrieving Joshua, as well as fullfilling her sense of justice (this becomes even more so in the Anime. Rosette is actually portraited as St. Mary, while in the manga this is not the case/have very evidence of being so). A demon crusader with a saint! ha ha....

Me thinkeths the manga paints a picture of Chrno being a more individual character who has very strong faiths (in Rosette, etc). In the anime, Chrno is more bounded by guilt and remorse. His love for Rosette is expressed with more delicate, romantic intends. I think Chrno's love for Rosette is expressed more as his insurmountable beliefs in her character.

Okay I am not trying to go off topic here...what I am trying to convey here is that Chrno behaves like a crusader. He has a strong faith in an 'idol'/God/Saint (in this case Rosette), he fights for a cause (against Aion & co. which makes the 'crusader' title even more appropriate).

[possible spoiler! highlight it to read.]

In the manga, he ultimately ends up in Pandemonium and together brings about the destruction of Pandemonium, the Legion 'colony' and *possibly* the end of Aion with the help from the 7 Apostles.

Mine you this is just the thought I have come up with in 2 mins. I have scarce knowledge regarding religions so please if you think I am totally off I do apologise for my ignorance....
:(