Three years later, in Pokémon Gold, Silver, Crystal, HeartGold, and SoulSilver, Brock remains the Gym Leader of the Pewter Gym, which can be challenged at any point during the player's travels through Kanto. He is surprised to hear that the player is from the Johtoregion, and happily accepts their challenge. While he doesn't give out a TM in Gold, Silver, and Crystal, he gives out TM80 (Rock Slide) in HeartGold and SoulSilver.
In HeartGold and SoulSilver, after all 16 Badges have been obtained, Brock can be found in Diglett's Cave near Pewter City on any day between noon and 3 PM, and will offer his Pokégear number if spoken to. If he is called on Saturdaynights, he will be up for a rematch at the Fighting Dojo in Saffron City. After his Pokégear number has been obtained, he will reappear in Diglett's Cave every day between 5 PM and 8 PM, and the player can have a photograph taken with him there. If he is spoken to in Diglett's Cave on a Saturday, he will offer to trade a Rhyhorn that knows Thunder Fang for a Bonsly.
"A TM contains a technique that can be taught to Pokémon! A TM is good only once! So when you use one to teach a new technique, pick the Pokémon carefully! TM34 contains Bide! Your Pokémon will absorb damage in battle then pay it back double!"
"There are all kinds of trainers in the world! You appear to be very gifted as a Pokémon trainer! Go to the Gym in Cerulean and test your abilities!"RB
"There are all kinds of trainers in the world! Some raise Pokémon for fights. Some see them as pets. I'm in training to become a Pokémon breeder. If you take your Pokémon training seriously, go visit the Gym in Cerulean and test your abilities!"Y
"So, you're here. I'm Brock. I'm Pewter's Gym Leader. My rock-hard willpower is evident even in my Pokémon. My Pokémon are all rock hard, and have true-grit determination. That's right - my Pokémon are all the Rock type! Fuhaha! You're going to challenge me knowing that you'll lose? That's the Trainer's honor that compels you to challenge me. Fine, then! Show me your best!"
"I took you for granted, and so I lost. As proof of your victory, I confer on you this...the official Pokémon LeagueBoulderBadge."
"Just having the Boulder Badge makes your Pokémon more powerful. It also enables the use of the moveFlash outside of battle. Of course, a Pokémon must know the move Flash to use it."
After being defeated
"Wait! Take this with you."
"A TM, Technical Machine, contains a technique for Pokémon. Using a TM teaches the move it contains to a Pokémon. A TM is only good for one use. So, when you use one, pick the Pokémon carefully. Anyways... TM39 contains Rock Tomb. It hurls boulders at the foe and lowers its speed."
"There are all kind of Trainers in this huge world of ours. You appear to be very gifted as a Pokémon Trainer. So let me make a suggestion. Go to the Gym in Cerulean and test your abilities."
"Small spaces surrounded by rocks make you feel peaceful, don't you agree? By the way, do you want to exchange numbers?"
Yes: "I would like to have a Pokémon battle against you! Give me a call on Saturdaynights!"'
Calling the player:
"This is Brock. Oh hey, how are you doing? There are so many different types of Pokémon in the world. As you could guess, I like Rock-type Pokémon best. They're solid and rough, and yet somewhat brittle at the same time. Once you've really gotten to know them, they're quite cute. What do you think?"
"Hello... What's up? I'm doing great! I can take a break on Saturday evenings, if you want to give me a call again then."
"Hello... What's up? I'm doing great! Hey, you called at just the right time! I'm free right now. Want to battle me again?"
No: "Is that so... Well, I suppose you must have a lot of things to do yourself..."
Yes: "All right, all right! I'm looking forward to it! I'll meet you at the Fighting Dojo in Saffron City! I won't be at the Pewter Gym, all right? Don't get confused!"
"All right! Time to fulfill our promise!"
After being defeated
"I've lost again... You aren't adventuring around for nothing!"
"Hi, Ash! It's good to see you again. It looks like I will be your first official battle. I hold the Boulder Badge. If you defeat me, then I will give it to you. Have you heard anything about the Puzzle Master? I hear no one has ever defeated him. Oh well, are you ready? Let's go."
In the anime, like later Gym Leaders, Brock appeared primarily as an opponent to Ash in his debut episode; unlike later Gym Leaders, he requested to join Ash on his journey, aiming to be the world's greatest Pokémon Breeder. In doing so, Brock left the Gym in the hands of his father, Flint, who had finally revealed himself to have returned from his journey. Brock advised Ash throughout the Kanto series, then left briefly during the Orange Archipelago arc to assist Professor Ivy. He returned to Ash's side in Johto, and with brief returns to Pewter City at the end of each series, joined him for his journeys in Hoenn and Sinnoh as well; however, he now wants to become a Pokémon Doctor.
Brock mainly provides an advisory role to the other main characters of the anime, being several years older than the rest of them. His knowledge of Pokémon battles is great, causing him to often referee matches between Ash and others. Brock also fancies himself as something of a ladies' man, though each time he hits on someone he is either rejected outright; pulled away by Misty or Max; or, more recently, Poison Jabbed by his Croagunk.
In Pokémon Origins
Brock in Pokémon Origins
In Pokémon Origins, Brock is the only Gym Leader to have a key role other than Giovanni. Much like his role in both the games, Brock is the Gym Leader of the Pewter Gym.
Brock is first seen in File 1: Red, watching a Pokémon battle between Red and Blue. After Red is defeated, Brock talks to Red and teaches him about the basics of Pokémon battling and training.
Later, Red discovers that Brock is the Gym Leader of Pewter City and goes to challenge Brock to earn his first Badge. There, they have a Gym battle in which Brock teaches Red about type matchups and strategy. Brock is shown to have many Pokémon, and selects Geodude and Onix when Red confirms that he has no Badges. This implies that all Gym Leaders have Pokémon of varying strengths in reserve in order to keep each challenge a fair fight. After a tough battle, Red eventually defeats Brock by using all of his Pokémon to slowly weaken Brock's Onix until it falls. Having lost the battle, Brock awards Red with the Boulder Badge and TM34 (Bide).
Geodude was the first Pokémon Brock used in his Gym battle against Red. It nearly defeated Red's Charmander, forcing him to switch out for his Nidoran♂, who was able to defeat Geodude with a Double Kick.
Onix was the second Pokémon Brock used during his Gym battle against Red. It manage to defeat Red's Nidoran♂, Spearow, Rattata, and Metapod. With the help of Metapod's String Shot reducing its speed, Onix was later defeated by Red's Charmander.
Brock, along with Ash and Misty, make cameo appearances in bonus chapters of the Magical Pokémon Journey manga. In the bonus chapters, Brock and co. have mistakenly wandered into the world Magical Pokémon Journey is set in. The bonus chapters chronicle their attempts to return to their own world (of the anime) and their encounters with various aspects of the Magical Pokémon Journey canon which differ from the anime's canon (such as the use of Poké Balls).
In the movie manga adaptations
Brock with his friends
As Brock has appeared in every movie prior to the Best Wishes series, he has appeared in every manga adaptation of it. His team in the manga adaptations are the same as in the films.
Brock debuts in Onix Is On! of the Red, Green & Blue chapter, however he is mentioned earlier by Blue in Wanted: Pikachu! about being bored by no one being able to defeat him, or even get past the preliminaries. To gain access to Brock, a Trainer must win several rounds of battles against special Trainers of the Gym, and all of those battles are watched by him from a special room.
Brock is a brave Trainer, and he assists Erika and Misty in their battles against Team Rocket. He also gave Yellow a Graveler after the good Gym Leaders of Kanto battled Agatha's mind-controlling Gastly. However, he is also shown to be quick to anger and restless in his search for a good battle, and when discovering that Red's Pika, the only remaining Pokémon of his, was disobedient, deemed his wins "dumb luck" and sought for a finisher attack instantly. However, when the boy begins to gain his Pokémon's trust, it chooses to fight for him and defeats his Onix.
After Blaine figured out that Red must have been at Mt. Moon before going missing, Brock volunteered to search there, since Mt. Moon is closest to Pewter City. He then found a cast of Red frozen in ice there and contacted Blaine. Before all of the information could be exchanged, he found out that Pewter City was under attack by a group of Bruno's Machop that was searching for Brock's Boulder Badge, and he left to protect it.
A few years later, he, along with Erika and Misty, traveled to Johto for the Gym Leader Tournament at the Indigo Plateau, where he faced off against the expert of the newly discovered Steel-type, Jasmine. He lost the match and later fought against Team Rocket on the Magnet Train.
Brock owns six Geodude, nicknamed Geoone, Geotwo, Geothree, and so on. One of them appeared in Onix Is On! watching the battles with his Trainer. The other five first appeared in Putting It On The Line...Against Arcanine. They often grasp each others' wrists in order to circle around Brock to protect him. During the Gold, Silver & Crystal chapter, they used their Magnitude to stop the Magnet Train. However, the impact sent it off course, causing it to almost crash before it was saved by Red's Snorlax.
Onix is arguably Brock's most powerful Pokémon and is apparently well known for its speed, which causes shock waves when it moves. Onix was first used in battle against Red's Pika. Despite the type advantage, Onix was defeated by the small Electric type after it came to fight for Red of its own will. Three years later, Onix was sent out by Brock to use as a bridge when a bridge in the Tohjo Falls went out while Brock, Erika and Misty were heading to Johto, during which Misty is joined by Suicune. However, it itself collapsed when they were all attacked by a large group of Zubat, Golbat and Crobat. Once the group finally made it to the Indigo Plateau, Brock used Onix in his battle with Jasmine. It lost to Jasmine's Steelix, which he initially mistook as an Onix of a different variety due to its rock covering used to hide the fact that it was a new, undiscovered species at the time.
Brock met Kabutops when it was a Kabuto in the Pewter Museum of Science during the Elite Four's invasion of Kanto, and received and later evolved it for protecting it during the ordeal. It knows many ancient attacks and is a very powerful member of Brock's team; it was able to easily hold its own against Jasmine's Amphy, nearly winning him the match despite the type disadvantage.
In the Pocket Monsters HGSS Jō's Big Adventure manga
Brock's only appearance in Pocket Monsters HGSS Jō's Big Adventure was in a flashback along with his Onix.
Brock in the Pocket Monsters manga
Brock in the Pokémon Ruby-Sapphire manga
In the Pokémon Pocket Monsters manga
Brock debuts in the chapter Take Out The Rival Onix!! of the Pokémon Pocket Monsters manga. Before Red arrived in Pewter City, Green got there and took Brock on. However, Brock was brutally strong as he managed to knock Green and his Charmander back into a window. The impact caused him to tell Red about Brock's strength. Despite Green's advice, Red decides to go to the Gym anyway. Red notices Brock's collection of Pokémon he had caught over the years and one of them turned out to be Clefairy's cousin, Pikachu. Brock then came and Red had his first Gym battle with him. Red used Clefairy while Brock used Onix. Clefairy managed to defeat Onix by having it chase its own tail, earning Red the Boulder Badge.
All cards mentioning or featuring Brock or his Pokémon in the Pokémon TCG are listed below.
Brock's Pokémon Cards listed with a blue background are only legal to use in the current Expanded format. Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.
In Generation I, Brock's Onix knows Bind at levels 12 and 14, despite Onix not learning the move until level 15.
Brock is one of two Gym Leaders not to give the player a TM of his specialty type, the other being Falkner. This is only true in Generation I, however, as in FireRed and LeafGreen, Brock's chosen TM changed from TM34 (Bide) to TM39 (Rock Tomb).