Most Powerful Characters in Heroes of Olympus

1.

Hazel Levesque.
Not only can she control metals, she can also use the Mist. So, if you even try to attack her, she could bend your sword or she could really confuse you by using the Mist.


2.

Percy Jackson.
This one was kind of obvious. Since he's a son of one of the most powerful gods, it makes sense. Also, Nico called him "the most powerful demigod he's ever met" (though I think Hazel is more powerful).

3.

Jason Grace.
Since he's the son of Zeus, the king of the gods it makes sense. Also, he can fly, summon lightning and create storms.

4.

Frank Zhang.

He's the son of Mars, one of the most powerful Roman gods, so that makes him pretty powerful. He's also a special descendant of Poseidon, which gives him the power of shape shifting. 

5.

Annabeth Chase.

She's done countless of deadly things. She's also the daughter of Athena, probably one of the most powerful Greek goddesses. And she always has a brilliant plan when you need one.

6.

Leo Valdez.

He's great with machines and can fix just about anything (except a flying  bronze dragon) . He also has fire powers.

7.

Piper McLean.

She's brave and follows her first idea: which can be good or bad. She also can charmspeak you into to doing anything. 

8.

Nico Di Angelo.

A son of one of the most powerful gods: Hades. He has power over all the dead spirits in the Underworld.

9.

Reyna Avila Ramirez-Arellano.

She is a daughter of Bellona, the Roman war goddess, so of course, she's great at battle. She also is a praetor of New Rome and is able to transfer strength to others.