Guessing the backstory of the lieutenant Apostles

Grunbeld: Already given to us.

Irvine: I'm guessing that he sacrificed a hunting partner (whether that be a human or animal), though I can't think of anything more.

Rakshas: We know that he was banished from the Bakiraka, but was that before or after he became an Apostle? If it's after, it'd be a pretty safe guess that sacrificing whatever he sacrificed is what got him banished.

Locus: I'm guessing that he was really loyal to his old master, but then his master did something bad that made Locus become extremely disillusioned and led to him sacrificing his master, and afterwards, as stated in the manga, Locus became a roaming knight who refused to become loyal to someone again until he found the right person.

Zodd: Based on Wyald and Rosine, it seems like Apostles transform into what their inner desires want the most. I think that Zodd was someone who really wanted to become a strong warrior, but lacked the talent or ability to become one, so once he finally realized that he could never accomplish his dream, his Behelit activated and he got transformed into an extraordinarily powerful Apostle.
 
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