^
Blade is a destoryer priest, not a particualry good priest but a priest none the less. Basically it seems he inadvertainly does hero stuff while satisfying his love of fighting, he came to Cruz in his hour of need and did not abandon him upon finding out he was normal (not just for the sake of getting a fragment). Hes not afraid of getting seriously hurt to do so.
http://www.onemanga.com/Needless/1/32/
Also when helping Kanna in sword of the reaper (that nice hold sword together momment).
He also a wandering soul, joining a guild and being seto's partner for a while, and its said that Blade had been gone again when Cruz brought him back to the church.
And he delivers devine punishment to evil needless by throwing their own misused powers back at them.
I doubt he had much in terms of goal other than to wander blackspots, see a lot of cute girls, help some people, smash up lots of other people, and live comfortably with Eve and Gido. But his clone brother's actions have made that impossible.
Even though technically it was who Cruz got him involved in the first place, it heavily implied that Blade would have wound up faceing Arclight anyway. And now hes in real danger of getting his body stolen, but he is the kind of person who would face death with a grin so i doubt he's cursing his situation. All these cute girls to meet, especially mio-tan who calls him onni-chan.
However on the matter of his situation.
A lot of people have critized Blade for his failures as a second clone but has anyone noticed he's not too fond of the circumstance of his existance.
http://www.onemanga.com/Needless/9/15/
http://www.onemanga.com/Needless/9/16/