Ash has had many companions over the years, but his longest and most consistent friendship has been with Brock. The spikey-haired lady-lover can boast multiple comebacks in Pokemon, with only Dawn to contend with for the most frequent cameos in the series.
After many fun-filled adventures, Ash's time came to go off on his own, while Brock and Misty pursued their own dreams in life. In 2002, the friends officially parted company in Gotta Catch Ya Later! (Original Series), and the Rock-loving, aspiring Pokemon Breeder has kept himself quite busy over the years.
9 Doc Brock – Diamond & Pearl
As many are aware, the main reason behind Brock's departure (in terms of the storyline, anyway) revolves around his ambitions of becoming a doctor, an upgrade from his previous dream of honing his talents as a Pokemon Breeder.
As the Sinnoh saga draws to a close, Ash heads off to the Unova Region while Brock remains in Kanto to advance his skills at the Pokemon Medical School. He graciously offers his assistance at the Pewter City Pokemon Center whenever possible, and to gain further experience, Brock takes on an apprenticeship in Johto with an established Pokemon Doctor. By the time The Arceus Chronicles comes to fruition, the young man seems quite efficient at his new profession in the Pokemon medical field.
8 Family Feud – Ruby & Sapphire
It is no secret that Brock hasn't got the best parents around, as he was solely responsible for caring for his many younger siblings when Ash and Misty first met the Gym Leader. His father, Flint, has since stepped up and given Brock some freedom, but things hit a snag once his mother makes an appearance.
After assuming control over the Pewter City Gym, Lola transforms the establishment into a Water-Type-only facility, much to the family's dismay. Flint fails miserably in re-establishing boundaries, and so, to save his rock-loving siblings from an aqueous-focused fate, Brock battles Lola for authority over the Gym. Onix lands the final blow and order is finally restored, leaving Brock with a clean conscious as he heads off to Hoenn.
7 Acquires A Key Stone – Sun & Moon
Brock has been absent for quite a while by the time the Alolan adventures roll around, but he has clearly kept up-to-date with all the new trends, and he proudly shows off his new Key Stone necklace (and bare chest, for added measure).
The young trainer certainly has something to prove during the epic battle against Kiawe and dominates the competition as soon as his Mega Steelix comes out to play. Although the specifics aren't discussed, many assume that Brock (and Misty) receives his Key Stone from Professor Oak sometime after Pokemon: Black & White.
6 Fell In Love, Again! – Sun & Moon
While Brock may be the biggest hound dog in Pokemon, nobody has captivated him quite as much as the enchanting Olivia, a cute Kahuna from the Akala Island of Alola. The suave young man declares his intentions to wed the woman of his dreams the moment he lays eyes on her. However, Olivia wants to battle instead and is captivated by Brock's skills before they are rudely interrupted by Team Rocket.
Long story short, the two lovebirds team up with Lycanroc and Sudowoodo by their side, holding hands to enhance their combined Z-Power to activate the ultimate heart-shaped Continental Crush move (get it?) The adorable cheese-fest gets topped off with fireworks but sadly ends with Brock accompanying the wrong girl (Misty) back to Kanto.
5 Made A New Friend – Black & White
Cilan has been accompanying Ash and Iris during their travels for the most part. However, he has taken some time for himself and subsequently becomes helplessly lost in the Johto Region. He is forced to rush Pansage to the nearest Pokemon Centre after an unfortunate mishap with a Gyarados, which is where Cilan officially meets Brock, who offers his medical services.
When Gyarados injures several more Pokemon, the boys combine their forces with Officer Jenny to subdue the waterborne beast, stumbling across a Pokemon poaching scheme along the way. After apprehending the criminals and saving Gyarados, Cilan gets to witness Brock's true passion in life and gifts him a new nickname, "Lady Connoisseur." The pair part ways without discovering their mutual connection through Ash (a common trend in Pokemon, it seems).
4 New Pokemon Companions – Sun & Moon And The Arceus Chronicles
During his holiday in the Alola Region, Brock (surprisingly) makes a good impression on Nurse Joy after assisting her at the Melelele Island Pokemon Centre and receives an adorable Comfey for his service. This lesser-known Fairy-Type does not get much screentime, besides offering a helpful hand in calming down a distraught Kangaskhan mother-and-child in "Heart of Fire! Heart of Stone!" Nevertheless, its Floral Healing makes it the perfect partner for Doc Brock.
Although Brock received a Happiny's Egg many moons ago (in Diamond & Pearl) it had not fully evolved by the time Ash and Brock split up. However, somewhere along the way, Brock's Happiny became a helpful Blissey assistant and has added (the unexpectedly offensive) Dazzling Gleam and Mega Punch to her Fairy fuelled skillset to kick things up a notch.
3 Helped His Brother – Diamond & Pearl
Brock steps into the paternal role once again when his younger brother, Forrest, finds himself at the back end of some unfortunate technical difficulties. Although Brock has not been the Pewter Gym Leader for quite some time, Flint failed to complete the official paperwork for new ownership, leaving his oldest son with the brunt of the responsibility.
Now that Forrest is old enough to take charge, he has been successfully running the Rock-Type Gym. However, the Pokemon Inspection Agency is unimpressed with the slapstick documentation. Thankfully, Brock is in the right place at the right time and convinces Nurse Joy to show some mercy, opening the door for Forrest to earn the Pewter Gym Leader title.
2 Became A Pilot – The Arceus Chronicles
For some or another reason, it seems that piloting an aircraft is a crucial skill for Pokemon Doctors, as Brock learned how to fly at some point in his training. According to The Rock Solid Trainer, taking a quick plane ride is the most efficient way to travel in the Sinnoh region (previously known as Hisui), and it is apparently his preferred method of transportation when making house calls to the locals.
While Ash and Dawn are desperate to get to Mount Coronet, Brock eases their anxiety by offering them a ride in his private, Pokemon-themed jet, as if it's the most normal suggestion in the world. The brief sci-fi scene is slightly out of place amongst the historical references. However, it gives Brock another chance to steal the spotlight.
1 Has a "Thing" With Jessie – Pokemon: Journeys
Pokemon villains clearly have too much time on their hands, as the infamous trio of tricksters takes (another) swing at showbiz with "Team Rocket's Undercover Kingdom Radio." Things don't get off to the best start in "Radio Lulled the Mischievous Stars!" so they decide to rebrand under the new name "Dum-Dum-Dum Z," and Brock happens to stumble across their content one day.
Failing to recognize Team Rocket's voices, Brock (and many others) gets particularly invested in the show and even sends some fanmail, which Jessie reads aloud on air. The pair share a bonding moment from afar, unaware of one another's identities but slightly smitten nonetheless.