Little Brother/Sister (3.5e Trait)
From D&D Wiki
You have a little brother or sister who follows you around constantly; he/she is annoying, but you love him/her with every fiber of your being.
Benefit: Your little brother/sister can be treated as familiar though they do not gain natural armor bonus, nor Intelligence bonus, but may deliver touch attack and gives a +2 moral bonus to one single skill check (chosen at the beginning). Protective Instinct: +2 to hit, +2 to damage when the child is threatened. if you intentionally put the child in danger(to benefit from this bonus),the child eventually figures it out and runs away. After incurring this bonus, you are winded for 2d4 rounds.
Drawback: If the brother/sister are in danger from an enemy you get a -2 to hit any enemy except the one endangering the child. If the child feels threatened by another party member or becomes sad/starts crying you gain a -3 to Diplomacy to deal with that party member till the child is cheered up. If the brother/sister has died, upon their death, you must make a will save DC 15 + Wisdom Modifier + age of sibling or go insane for 1D4 years.
Special: If the child has grown to adulthood, one of three possibilities may occur; If the child was well cared for the character may gain a cohort(doesn't take up companion slot). If the child was cared for moderately then the child may just move on with his/her life and leave you to peruse their own dreams. If they were put in harm's way to many times, he/she may turn evil. This is based on the DM's decision and discretion.
Roleplaying Ideas: You love him/her, he/she your best friend, your confidant. Don't put him/her in harm's way. Even if you're evil, he/she is YOUR little brother/sister. You can also use him/her to carry your belongings. You may want him/her to have the best food, the best place in the inn. He/She may even annoy other party members, but you don't care, come on he/she is still a child, you can't blame him/her. In combat, tell your little brother/sister to hide; you don't want them to be eaten or kidnapped. If you're evil enough, during a particularly dire time, you may use them as a source of food; though, if you took this trait in the first place, why would you willingly kill them off just as easily? Only for -extremely- evil people.