Youngest son

Even when not scorned as small and weak, the youngest son is seldom distinguished by great strength, agility, speed, or other physical powers.

[3] He may be particularly clever, as in Hop o' My Thumb, or fearless, as in The Story of the Youth Who Went Forth to Learn What Fear Was, but more commonly his traits include refusal to abandon the quest, as in Tsarevitch Ivan, the Fire Bird and the Gray Wolf or The Brown Bear of the Green Glen, and courtesy to strangers, especially those who appear weak, as in The Water of Life or The Fool of the World and the Flying Ship.

[5] This success may make his brothers an additional obstacle, as in The Golden Bird, where they overpower him and steal what he has won on his quest.

In some tales, such as The Grateful Beasts, they conclude he may be a rival in advance, and they attempt to stop him before the quest; in others, such as Thirteenth or Boots and the Troll, he must set to tasks because they have spitefully claimed that he said he could.

The White Bear in East of the Sun and West of the Moon marries the youngest daughter; in the Black Bull of Norroway, the heroine's older sisters set out to seek their fortunes before her.

In Diamonds and Toads, the younger-&-least favoured daughter of a widow marries a king's son (after having passed a 'Test of Character' administered by a fairy in disguise).

Andrew Lang has his Prince Prigio jeer at the notion that he should go first on the quest, when he is the oldest son; only after his two younger brothers have not returned can he be compelled to go.

Likewise, in Diana Wynne Jones's Howl's Moving Castle, Sophie, being the oldest daughter, is resigned to having the worst chances to make her fortune, but is precipitated into the plot by evil magic.