Wrath

The Title of King Bradley was a cover up for his true mission from his leader, "Father" who is the supposed father of all the homonculi. Wrath is unique out of all of the Homonculi because of on thing : he aged. So, regardless of what he seemed like, he would never be suspected by anyone. For a long time, people in the government of Amestris assumed that there was a mole among their ranks. Never did they expect that the "mole" was their leader.
 Also at multiple points in the fullmetal alchemist story line he is seen to help the Elric brothers and give them melons.
 
 

Powers and Abilities

Unlike other homunculi, Bradley was originally human and was the result of experimentation with the philosophers stone.   He does not possess the same regenerative abilities but is still more durable then a normal human.  Bradley's most notable ability is his ultimate eye, the eye covered by his patch.   This gives him incredible eyesight far beyond any normal human, and allows him to easily read and predict his opponents movements.  
Bradley also possesses unrivaled skill with a sword, being able to slice through steel with ease and being able to wield multiple swords simultaneously.  His skill with a sword and his inhuman speed make him one of the most formidable and dangerous combatants in FMA, Being able to demolish tanks and entire platoons of soldiers and being able to battle several Xing warriors at once and dominating the fights.