Iggy Koopa

Not much is really confirmed in detail about Iggy's personality, and what could be considered confirmed comes from other official Nintendo sources like the Nintendo Adventure books and does occasionally clash with what we see in other things. There are some inconsistencies there too though, so this section is using what is the most consistent.

Iggy is one of the more unpredictable of the Koopalings, and his intelligence is likely only second to that of his oldest brother, Ludwig, if any of them at all. He's often giggling and seems to be pretty hard to get riled up or actually upset. It's stated that he often speaks in a cutesy manner, and in the non-canon Mario Is Missing he does speak in rhyme. The emotional distress of others is something that he really enjoys, along with just making life inconvenient for others overall where he can. He doesn't to be super ambitious or evil all on his own, and is more of a trickster who just happens to like to see people suffer a little emotionally.

Described as a "crazed mechanical Koopaling genius", Iggy is likely often the engineer of the various war machines used by his family, also being addressed as "the brainy one" by Bowser in the Nintendo Adventure book Double Trouble; which was part of a series of Choose Your Own Adventure books that were based on the games. he takes great pride in the things that he builds and what they can do, but if things in his plans go the wrong way then he may become annoyed at that point. Even though he is considered a mechanical genius, Iggy still uses his magic wand to help in battle while some of his siblings have somewhat abandoned theirs for other tactics. This, and the fact that he has done like his siblings and relied on Kamek's magic, would mean that he doesn't scoff at the usefulness of magic.

The fact that, in both Super Mario World and New Super Mario Bros. Wii, he is the only one of the Koopalings whose battle can't be skipped by Mario taking the fastest routes could imply that he is also one of the more reliable siblings compared to the others since it's likely that Bowser decides where they stay most of the time. And despite losing to Mario quite often, Iggy doesn't seem particularly afraid of him and has no qualms taunting him before battles by pretending to be scared before laughing it off or slapping his rear end at Mario. Even if he's certain that he can't be reached, it doesn't phase him much if the enemy does make it to him. He'll just use whatever is on-hand to try and take his opponent down.

The more recent games imply that he's fond of and good with Chain Chomps, as when fighting MArio on two occasions he is using a carriage pulled by one that gets mad and more aggressive whenever Iggy is hit. This is somewhat confirmed by a comic, though that comic pins him as cruel and neglectful enough to let his pet get lost, trapped, and nearly starve while blaming it for that by calling it stupid, which resulted in it turning on him. But Chain Chomps are usually hard to control and short-tempered, and aren't often seen to be loyal in most of the games where they appear under the control of other baddies, acting indifferently to those that should be their masters and even damaging them. Iggy's, however, pulls him along obediently and tries to hurt Mario every time he lands a hit on Iggy.

Across the various Super Mario media, it is often shown that he seems to favor his brother Lemmy the most of all of his siblings. This may be in part because of their somewhat similar appearances, but is most likely because they're both mostly pranksters that happen to be bad guys. He sometimes doesn't really think much of Bowser, who isn't the Koopalings' real father in the first place, and actually thinks that he is pretty dumb overall...but he also knows better than to say so or to intentionally get on Bowser's bad side for the most part. But he does seem to be loyal for the most part, even helping the other Koopalings combine magic to help him gain an advantage or trying to help get him back on his feet after Mario wins in the newer games. It also seems that he may not hold any resentment towards Bowser Jr. despite him having come into the picture as Bowser's legitimate kid and heir, as in two of the games he appears alongside Jr. he is the next Koopaling directly after his first defeat. His feelings toward most of his siblings aren't really covered, but he may be somewhat afraid of Roy, who is at times portrayed as prone to bullying his siblings.

Abilities
Iggy is a mechanical genius and the brains behind most of the technology used by the Koopas. But he isn't just an egghead, he's a fast-moving kid with energy to burn. He's not the physically strongest or most resistant to damage, but like all of his siblings, he can take what's dished out and recovers fairly quickly...if only so he can make a quick getaway. He's the tallest and lankiest of the Koopalings, being only a little shorter than Bowser himself, which gives him more reach than any of them.

He's faster than all of his family and can even run and stand on the ceiling with no effort. He's capable of tucking into his shell to spin around rapidly in place or while moving, and is faster than his siblings in this too as evidenced by the higher whirling sound that is emitted when he does so.

As a koopa, he's also capable of spitting fireballs and is relatively resistant to fire and lava, considering several boss fights directly require knocking him into lava but he continues to appear in later games. Unlike the weaker koopas that Mario encounters, Iggy and the rest of his family don't have a full shell. Instead his shell sits on his back and he seems to have a padded stomach that expands into a proper stomach plate when he withdraws into his shell.

Iggy is often seen carrying a magic wand, and knows at least three spells. The first is firing chaotic bursts of green magical energy, and the second is firing red orbs that can damage on contact or summon Magmaargs when coming into contact with lava. He also can use a growth spell, but may need help from his siblings to make the spell work to its full potential. In the non-canon Hotel Mario he could summon lightning.