Does "nii-san" really mean brother-in-law, though? I know that's how it's meant in this context, but I'm pretty sure it generally translates to "brother" in a less lovey-dovey tone than "onii-chan" but not quite as formal as "nii-sama" or the semi-archaic "aniue."
@VincentYamato
He starts out at level 30 instead of level 1, with all the skill points he'd have earned from the 29 level-ups. But in exchange he gets no class-exclusive skills. He can only do stuff everyone else can do. No magic, only basic alchemy, etc.