Seems like half-breeds get the lousy end of inherent skills. Yeah I know, bastards don't deserve anything. But I am a fan of half-breeds, so :

Ability : Racial-bias
Race : Half-halfs, half-drows

Command : Only at character creation. A half-breed can choose the 'affliation' of their heritage. Eg. a half-drow can select to be more human or drow affliated. Having chosen, the half-breed then has a alightly weaker inherent skill.

_OR_

Command : Only at character creation. A half-breed can have two of the inherent skills from both human and (dark-)elf races but at half their strengths.

Skill affects : Half-breeds are considered outcasts and rarely embraced by human or (dark-)elfs alike as one of their own. Their ability to adapt due to the trait in their 'human' blood, they have retained limited knowledge of their racial skill. This has enabled them to survive in the hostile dislike for half-breeds. However, they only have limited or weaker use of their racial skills.