This bring a tiny bit of conflict in Episode 21, where Joey and Psy are led to believe that Lina's brother Will kidnapped Holly. On one hand, Joey admits that he would hurt anyone who hurts Holly, but Joey doesn't want to indirectly hurt Lina either.
Barrier Warrior: He comes up with uses for his energy shield that catch his less canny foes offguard.
Disguised in Drag: Invoked when he (or rather, his older sister insists that) he needs to sneak into a hospital to talk to one of the patients. Interestingly enough, he didn't have to alter his appearance much; he just needed to put on a dress. Which leads us to...
Dude Looks Like a Lady: He greatly admires his father and strives to be like him. Alas, genetics being the fickle bitch that it is, he favors his mother instead. Greatly favors. As in, looks exactly like her.
Indy Ploy: A dab hand at on-the-fly improvisation and inventive use of his and Heroman's powers. Forget the Kamehame Hadokens and Force Fields - it's when he brings out the magnets that you should really be worried.
Humongous Mecha: Although his usual size isn't that big, (he can fit inside some buildings if he crouches) he transforms into a ,ore generic case at one point in the anime.
Empathic Weapon: His power growth seems to be directly related to Joey's Character Development. Also bears more than a passing resemblance to Joey's personal hero, his father. Hmmm...
Handicapped Badass: Being unable to walk properly does not seem to impede him from riding a skateboard, assisting the professor in his plans, and even kicking ass right alongside Joey with a sweetass guitar.
All Guys Want Cheerleaders: A rare inversion: it's our cheerleader who really wants the average, "nerdy/loser" hero, much to her brother's chagrin — Lina is more to take the initiative on her feelings, while Joey's a bit more subtle and reserved about it.
Conflicting Loyalty: Develops this when she grows torn between heeding Will's warning to stay away from Joey. That, along with Joey lying to her about seeing Will again, only settled her doubt in him.
Tag Along Kid: Insists on following Joey and friends into the city during the Center City invasion arc, despite being the only one to not join in the fight against the leader of the Skrugg. This fact allows her to avoid becoming The Load, however.
The Woobie: Lina's progress in her relationship with Joey tends to get dampened by her separation from her brother Will and by constantly getting Locked Out of the Loop by Joey and the others. The latter doesn't sit too well with Lina in Episode 23 when she discovers Joey kept it a secret that he previously encountered Will.
Matthew "Professor" Denton
The science teacher at Joey's school whose successful contact with aliens led to the Skrugg attack on Central City.
Adult Child: Often seems rather less mature than his teenage friends.
The Atoner: Mild case. He feels it's his responsibility to help Joey fight the Skrugg. After all, he told them where Earth was in the first place. This being a light-hearted kids' show, he doesn't spend much time angsting over it.
Cool Big Sis: Shows very faint glimmers of this on occasion.
Crazy Awesome: Investigating serial kidnapping in Central City? Forcing Joey and Psy to dress like stereotypical detectives? In attempt to lurk into hospital forcing them all to Recursive Crossdressing? Drinking so strong coffee with so much sugar that her head would explode?
Parental Abandonment: Unlike Joey who was too small to remember their father, Holly can't forgive him for dying in an act of heroism, which she saw as abandonment.
Break the Haughty: Dear Lord. Not only does he pretty much lose everything he's ever had in a moment of jealous spite, but all the power he's gained hasn't prevented the Skrugg from doing one damned thing.
Hidden Depths: Yes, he bullies Joey for seemingly no reason, And That's Terrible. But at the same time, he truly does bear sincere love for his sister, and really only wants to protect her and be her hero. He is also revealed to have a strong sense of the responsibility when he stepped down as Captain of the football team, not considering himself worthy after he indirectly caused Psy's disability.
Not So Stoic: His stern, contemplative appearance takes something of a dent in Episode 16, when he reacts to Heroman obliterating the MR-1 with a loud, enthusiastic, Hiro Nakamura-esque "YATTA!" See also: Crowning Moment of Funny.
Smug Snake: He is the one who was putting pressure on President to do "something" about Heroman. And he also without knowledge of the President ordered research on Koggor's eye, what didn't end well.
Evil Chancellor: Subverted, despite being clearly a Smug Snake he warns President about Skrugg attack and escapes with him to the bunker.
Antagonists
Kogorr
The leader of the Skrugg and the resident Big Bad.
Bad Boss: All the way up to eating his subordinates. The Skrugg really ought to charge for workers' comp.
Dangerously Genre Savvy: In a series filled with Dangerously Genre Savvy antagonists, he takes the cake, starting with little things like failing to ignore the big nasty robot chewing through his forces, and going all the way up to faking an obvious weak spot in his Eldritch Abomination form in order to lure Heroman into a trap.
Disc One Final Boss: Subverted - he got taken out within the first nine episodes, and then returned in style for the series climax.
Why Won't You Die?: Says this when Heroman shows up again to stop Joey's kamikaze attack. Considering that Heroman had his entire abdomen annihilated moments prior, this is understandable.
Dr. Minami
An Evil Genius with connections to the White House and the military.
Dangerously Genre Savvy: Does not ignore the flaws in MR-1 and actually improves upon them. He's also capable of spotting and ruthlessly exploiting Heroman's own deficiencies.
General Ripper: Does a rather good job of being this despite not actually being a military officer, thanks to his ties with the armed forces and obsession with Heroman.
The Napoleon: Takes increasingly-ridiculous measures to compensate for his diminutive stature, culminating in dangling from his team's tilt-rotor like a tiny green-and-white marionette.