From Bulbapedia, the community-driven Pokémon encyclopedia.
Flint (Japanese: ? Munoo) is a Rock-type Pokémon specialist. He is the father of Brock, Forest and eight other unamed children. He is married to Lola.
For quite some time, he was the Gym Leader of the Pewter City Gym, and gave out the Boulderbadge to challengers who defeated him.
In the Anime
Ash and Misty had just made their way out of the Viridian Forest. Ash was eager to get his first Gym Badge.
On the outskirts of Pewter City, Ash met Flint, who was selling rocks as souvenirs. Ash bragged about his goal to become a Pokémon Master, but Flint told Ash that thinking he could defeat Brock was foolish.
In the match, Pikachu was defeated and injured and Ash lost the match.
Flint brought Ash home, and talked with Ash about Brock. He said that Brock had many talents that he could use to become more than a Gym Leader.
Flint took Ash to Brock's house and revealed that Brock had ten younger siblings that he constantly had to take care of, because his father left to become a Pokémon trainer who never returned, as did his mother.
Ash began to feel guilty over fighting Brock.
Flint was surprised that Ash wanted a rematch and told him of a way to super-charge his Pikachu. Flint took the boy to a hydro-electric dam and told Ash that he could hook Pikachu up to the generator and increase it's strength, however the river had run dry. Ash decided to turn the wheel himself to strength his own Pokémon.
In the Gym, Pikachu's electric attacks set off the Gym's sprinklers, which weakened Onix, allowing Pikachu to knock it out. He refused to accept the Badge, though, because he didn't win it fairly.
Brock caught up with Ash and gave him the badge anyway, saying that he didn't want to be a Gym Leader, but a Pokémon Breeder, but he could't leave home because of his responsibilities to the Gym and his family.
Flint showed up and revealed himself to be Brock's father. He had failed to become a successful Pokémon trainer and couldn't face them. Thrilled, Brock left the Gym Leader position and the duty of being head of the family to Flint.
At least a year or two later, Brock returned to Pewter City after traveling through Kanto, Johto, and the Orange Archipelago. Flint tried to sell him some rocks before recognizing Brock. Brock started to yell at Flint for not taking care of the Gym.
An embarrassed Flint explained that that he had just got the Gym set up the way he liked it when Brock's mother returned.
Flint took Brock back to the Gym, which has been redecorated. Flint closed it because he couldn't stand it anymore.
Back at home, Brock's ten siblings were all happy to see him. His mother was decorating the house. Brock said that the house didn't look so bad, but a glum Flint told him that the Gym was much worse.
Brock's mother had filled the Gym with water, pink streamers, and paintd stars everywhere. A very sheepish Flint tried to go unnoticed ash Brock starts yelling at Lola.
Lola gushed over her own work and showed off her Water-type Pokémon, and said that they were much better than Rock-types. Brock demanded to know how he let this happen, and Flint explained that he just couldn't say no to his wife.
Lola and Flint had a rematch for the title of Gym Leader. Flint was sure he would lose due to a type disadvantage, but Brock pressured him into the battle anyways.
Lola called out her Marill, and Flint used a Golem. Flint's Golem was trapped on a small rock in the Gym's water. Golem tried to use an Earthquake but Marill used the waves created to vibrations to sweep away Golem with Surf.
Flint was almost ready to run away again, but after some flirting, Lola and Flint ended up being lovey-dovey with eachother and the two aggreed to change the Gym to specialize for Water-types.
Brock decided to Battle his own mother to keep the Gym the way it was. Brock had a match with Lola and was victorious. Lola said she would give up trying to change the Gym's type. Brock passed on the title of Gym Leader to his eldest brother, Forest, along with most of his Pokémon.
Flint gave Brock his first Pokémon, an Onix, for a birthday present. It's become sort of a family heirloom, as Brock has passed on Onix to Forest.
This listing is of Flint's Pokémon in the Pokémon anime.