Blackjack the Pegasus

 Blackjack is a pegasus, one that Percy freed off of the Princess Andromeda in The Sea of Monsters. Blackjack now considers Percy his boss, coming to his aid in many situations. Blackjack also has two friends, Porkpie and Guido, who also come to help Tyson, Annabeth, and Thalia.

Blackjack is known to be very fast, getting from San Francisco to Manhattan in just hours, as shown in The Titan's Curse.

Blackjack is known to be very curious, asking Percy if he doesn't come back, if he can have Percy's cabin. Of course, this never happens. Blackjack also likes Percy more than Tyson. He claims that Tyson is "Huge." But somehow, Percy always convinces Blackjack and his friends to let Tyson ride on them, promising extra sugar cubes and apples. The pegasi always give in, knowing they like sugarcubes and apples.