When the player is cornered by the Seven Sages, Clay is the first of the Unova Gym Leaders to march in. He asks the player if he is tired out yet, then the rest of the Unova Gym Leaders, with the exception of Cilan, Chili and Cress, walk in and take positions opposite each sage in pairs. Drayden then tells the player to proceed in pursuit of N.
Once the player gains access to the Driftveil Gym, Clay will be standing outside of the Gym, opposite Ghetsis and some Team Plasma Grunts. Ghetsis refers to Clay as the "Miner King".
When the player encounters the Driftveil Gym Leader inside of Twist Mountain on his/her first visit after obtaining the Mistralton Gym Badge, he will say that Twist Mountain belongs to him, and that the player and Cheren can train on it should they wish to do so.
One of the Trainers the player can battle inside the Driftveil Gym says that Clay is a company president. However, it is not known what business Clay actually owns. Another Trainer that can be battled inside the Driftveil Gym says that Clay stays at the bottom of the Gym to remind himself that he once had nothing. A backpacker inside the Nacrene City Pokémon Center says that Clay found Fossils on Twist Mountain and donated them to the Nacrene City Museum.
In Pokémon Black 2 and White 2, he returns as a Gym Leader. The TM Clay gives away remains the same, though he gives it out immediately after the battle rather than outside Chargestone Cave, as there is no longer any Galvantula web blocking the entrance.
After the Gym battle, Clay will take the player up his private lift to the entrance of the Gym and then leaves. Outside of the Gym, he is with Hugh and notices that the player and Hugh are friends, and then proceed to show the two Trainers to the Pokémon World Tournament south of Driftveil City. Once there, he goes inside and tells them both to join in the Driftveil Tournament. Cheren is already there and participates as well. After the tournament, Roxie turns up and learns about the tournament, and leaves again. Clay follows and leaves the player to continue the adventure.
"Hrmph! So yer the Trainer Elesa was talkin' about, huh. I'm Clay. I'm the Gym Leader 'round these parts. Don't be expectin' no welcome, now. 'Cause when we lowered that bridge, the Team Plasma guys we'd caught done escaped in all the ruckus!"
"Ya can say whatever ya want. But what's important is y'all showed up, and then Team Plasma escaped. Maybe it's a little heavy-handed, but you oughtta start lookin' for Team Plasma, too. Yer both talented Trainers, aren't ya? Tell ya what... If ya find Team Plasma, I'll let ya challenge my Gym! Life's all about give and take!"
"Well, I'll be! Hidin' in a chilly old place like this... You guys take these Pokémon robbers!"
"You guys ain't so bad! Yup, a promise is a promise. Come on an' challenge my Gym!"
"I don't need no thanks, now. Yer buddies were tryin' to steal some folks' Pokémon."
"Well, that sounds real nice, if it's true. I may not talk purty, but at least I'm an honest man. You talk real nice, but what yer sayin' kinda sounds like lyin'. So tell me plain, what are ya tryin' to say?"
"...Well, I can't tell if yer lyin' or not, but I reckon you've won this without a fight. Hrrmph. Fine. Take 'em and git!"
"Sorry to let Team Plasma go after you tracked 'em down, fellas. Say, why don't we cheer ourselves up with a Pokémon battle? Don't keep me waitin'!"
"Well.. Think it's about time fer myself what it is about yer skills that makes a Gym Leader like Elesa take such a shine to ya."
During battle (the first non-KO HP loss)
"Well I'll be! Sure didn't see that coming."
After sending out last Pokémon
"Givin' up's the easy way out! If I wanted, I could have given up any old time!"
"Well, I've had enough... and just so you know, I didn't go easy on you."
After being defeated
"Mrrrmph. I see. But I sure don't like it! Fer such a young 'un, ya have an imposin' battle style. I know ya got people who can dig up yer potential. Mrmph. Here! Take this!"
"So this is yer fifth Badge, huh? If that's so, Pokémon up to Lv. 60 will obey ya. Also, I'll give ya this TM. ...Well, that was the plan, but I just remembered there's somethin' I want. Wait in front of the cave at the end of Route 6, wouldja?"
"What's the problem? Go wait in front of the cave at the end of Route 6!"
"I don't know how much potential ya got, but if ya think ya can go, go wherever, and if ya think ya can do somethin', keep doin' it. Do things how ya want! Decide yer own limits."
"Mrrrmph! You, huh? Remember what I done told ya? If ya think ya can go, go wherever, and if ya think ya can do somethin', keep doin' it. Do things how ya want! Decide yer own limits."
"Thanks fer waitin'. Looks like th' nest of an Electric-type Pokémon called Galvantula. Don't know why there's a nest here, but if there are folks havin' problems, th' Gym Leader's th' one ta fix it. Krokorok! Take it out! And this here TM's yours. It's my favorite TM, so ya can teach it ta all of yer Pokémon! It's called Bulldoze. This move does damage and lowers the Speed of any Pokémon it hits. Some Ground-type Pokémon move a little slower than ya'd like. If ya use Bulldoze right, ya can cover that weakness! I don't know how good you really are, but if ya think ya can go, go wherever, and if ya think ya can do somethin', keep doin' it. Do things how ya want! Decide yer own limits."
"What a surprise. Seein' ya here while I was inspectin' Twist Mountain. Th' two of ya seem a bit more rugged than the last time I saw ya. A li'l bit, anyway..."
"By th'by... You folks seen that Team Plasma crowd lately? After all the trouble, we Gym Leaders met up and had a chat. But we've got no clue where they are. It's like they're hidin' under a rock. Well, not much to do but wait for 'em to move. Anyhow, this's none o' yer concern. Squirts like the two of ya should just enjoy travelin' with yer Pokémon. Twist Mountain's a fine place to explore! You'll have some fun if you just leave this here path... Weeell... Better ya just see it yerself, 'stead o' listenin' to me yammer. Be seein' ya, sprouts! Feel free to train yerselves on my mountain fer as long's ya like."
"Mrrmph! You, huh? Remember what I done told ya? If ya think ya can go, go wherever, and if ya think ya can do somethin', keep doin' it. Do things how ya want! Decide yer own limits."
In front of the Gym
"Oh, so you two squirts know each other, huh? Ya both ain't bad, so I wanna show ya somethin'."
"There's always room for folks to grow and change, ain't there? And, if ya only go after what ya think is right, ya might end up rejectin' all thoughts and opinions other than yer own. That's mighty dangerous."
"Well then, I'll be waitin' for you at the south end of town!"
Pokémon World Tournament
Introducing the Tournament
"Here we are! Whaddya think? Great buildin', huh? Here's where the Pokémon World Tournament takes place! Ain't she purty? Follow me, tads!"
"This time, I'm gonna have ya participate in the Driftveil Tournament. Anything goes in this here tournament! Eight people will be participatin', and if ya win three times, yer the champion!"
"Ya know somethin', Cheren. The one who's gotta show everyone what Pokémon battlin' means--is you. And yerpal ain't here, either! I'm countin' on the power of youth, 'cause everyone likes up-and-comin' stars! OK! Whenever yer ready, get on over to reception!"
After the Driftveil Tournament
"An outstandin' battle, runts! Now everybody's gonna want to join in on this here tournament an' show their stuff!"
"See what I mean? People are pourin' in already! If the strongest Trainers from all over join in, it'll raise up everybody's level of skill! An' then, li'l ol' Driftveil City will grow even more and make a heap of money! So keep on bustin' those battles and rilin' everybody up! See ya!"
Before battle (first round)
"Yer tougher than ya were when I gave ya that Gym Badge, right? Well, how 'bout we have ourselves a look and see what ya can do now."
Before battle (second round)
"How much stronger ya get comes from how much you want to win! Always be loyal to that desire, ya hear?"
Before battle (final battle)
"If ya want ta win, don't make excuses! Got it? If yer gonna bellyache, just forget 'bout fightin'! Well, I might be fussin' 'bout nothing when it comes to you."
"Well, I've had enough... And just so you know, I didn't go easy on you."
If the player is defeated
"It's simple, hear! I wanted to win more than ya did!"
After being defeated
"Fer such a young 'un, ya have an imposin' battle style. I wonder what kind a journey ya had that made ya so strong. But, I still don't like losin'!"
"What's important is how ya react to losin'. That's why folks who use losin' as fuel to get better are tough."
In the lobby, after the tournament
"Am I all right with a Trainer like ya winning the Tournament, ya say? Ya think there're stronger Trainers out there yet? Talented Trainers who think like that are just who I want to come here to Driftveil City!"
(to Burgh) "Found a Fossil in Twist Mountain. I came here to have Lenora look at it and see if ya wanted to keep it here or somethin'."
"Hmm? Well now... No matter who ya are or when ya die, bones are all that'll be left of ya. When ya think about it, it's amazin'. Even if ya die, ya can make money! Some Fossils are worth a lot, ya know!"
(to Lenora) "Here ya go! Whaddaya think? It's gotta be worth a mint as a specimen or as a collectible! Which is it?"
"That so? Guess my Twist Mountain still has unlimited potential! All right! I'll keep on diggin' my Clay Tunnel! Here, Burgh! That plain ol' Fossil's yours! Have a look at it and think about what bones mean to ya."
Jingle: "Woo hoo! All right! It's 'The National Gymquirer'!"
Page: "That's right! We collect the hottest gossip about Gym Leaders seen around town! Here is today's letter. From someone going by the name Veildrifter. Thank yooou! 'You know how Gym Leader Clay never takes off his hat? Well, the other day I finally saw him take it off... And underneath his big hat was a fluffy knit hat! He wears two hats! Weird, huh?' Hmm... That seems like it would be way too warm! Still, I wonder if that isn't just Clay's hair sticking up all funny... 'The National Gymquirer'! We eagerly await your letters!"
Clay made his first appearance in The Mighty Accelguard to the Rescue!. Ash and his friends met him right after they had arrived at Driftveil City, and Ash asked him for a battle. However, he refused to battle Ash at the time because he had to check out a mine at the edge of town. Ash would try to battle Clay again in Stopping the Rage of Legends! Part 1 but he refused yet again. He claimed that he could not have a battle with him if he did not have any Revival Herbs. When Ash asked what they were, Clay criticized him for not knowing and said that he probably wouldn't be worth battling. However, he did promise a battle if he brought him some Revival Herbs.
Clay is shown to have started his life as a miner when he was around Ash's age with his Excadrill. One of his mines would later become the Driftveil Gym. He greatly values experience through hard work and views Ash's youth and inexperience with contempt, though he later gains new respect for the young Trainer after their battle. Clay prefers a frontal assault style of battling and becomes enraged when Ash uses strategy like his Snivy's Attract to stop his Palpitoad.
Clay's Palpitoad first appeared in Battling the King of the Mines!, where he was used in a Gym battle against Ash. He easily defeated Ash's Oshawott, after which he battled with Snivy. Snivy started by using Attract on Palpitoad, which became infatuated, thus making him unable to attack and an easy target for Snivy, which hit him with all of her attacks and finally defeated him with a Leaf Storm.
Clay's Excadrill was used in a Gym battle against Ash's Snivy. It was easily able to block all of Snivy's attacks and then knock her out. Next Ash used Roggenrola. Thanks to its AbilitySturdy, Roggenrola could avoid being knocked out by Excadrill's Horn Drill. Later Roggenrola evolved into a Boldore and defeated the Subterrene Pokémon with its newly learned Rock Blast and Rock Smash attacks, despite being at a major disadvantage.
Clay makes his first appearance digging around Desert Resort. When one of his men finds a mysterious rock, Clay tells them to just ignore it. When Clay touches the stone, he experiences a surge of power rush through his body. He reports his find to Lenora and asks her to come take the stone and investigate it. As they talk, the Shadow Triad spy on Clay and plan to steal the stone from him.
When Black travels to Driftveil City to get his fifth Gym Badge, he finds that the drawbridge is currently down for maintenance. Elesa tells Black that Clay is currently trying to fix it, but Black decides to just travel on the drawbridge anyway. There, he encounters N's Zorua, who had sabotaged the drawbridge and prevented it from moving. After driving it away, Black meets Clay, who he initially mistakes for being another one of Zorua's Illusions. They quickly clear up the confusion, but Clay attacks Black for being insulted earlier.
Upon arriving in Driftveil City, Black is unable to have his Gym battle due to Clay's bad mood. Clay decides to let Black have his battle after realizing that he could help with the stone he found in Desert Resort. As they battle, Clay tells Black that the stone he found was actually the Dark Stone, the stone form of the Legendary PokémonZekrom and that Team Plasma is currently aiming on stealing it. Clay also reveals that the Gym Leaders are fully aware of this plan and that they intend on joining together to stop the Shadow Triad from getting the Dark Stone. After losing the battle, Clay takes Black to the Celestial Tower at Mistralton City to meet up with the other Gym Leaders.
When Black comes to have his Gym battle, Clay reveals that the stone he found was actually the stone form of the Legendary Zekrom and that Team Plasma aims to steal it. Clay also reveals that the Gym Leaders are fully aware of this plan and that they intend on joining together to stop the Shadow Triad from getting the Dark Stone. After losing the battle, Clay takes Black to the Celestial Tower at Mistralton City to meet up with the other Gym Leaders. Once Skyla finishes her Gym battle with Black, she takes the group to Nacrene City to help Lenora after she had already began her battle with the thieves. Although they manage to win with teamwork, the Shadow Triad reveal their trump card, the Legendary Pokémon Tornadus, Thundurus, and Landorus. They use the three to defeat and kidnap the Gym Leaders to prevent further interference.
Clay and the other Gym Leaders were taken to a dark room in N's Castle. They had their memories tampered with so that they do not have any recollection of how they were kidnapped. When searching for a way to rescue the Gym Leaders, Caitlin used psychic abilities to communicate with the Gym Leaders. She was unable to find out their location, but she found that the Gym Leaders were unharmed. She also used her powers to relay a message to Black in his Gym battle against Drayden.
During Team Plasma's attack on the Pokémon League, Clay is hoisted up on a crucifix along with the other Gym Leaders so that they and the League can be mocked. Black tries to save them, but is stopped by Ghetsis and the Seven Sages. With no way to rescue his friends, several Trainers that Black met on his journey arrive to rescue the Gym Leaders in Black's place. Through teamwork, the Trainers manage to free the Gym Leaders from their bindings. The Gym Leaders then help to stop Team Plasma from attacking the League.
Excadrill is Clay's first known Pokémon. It was first seen digging up a mysterious stone at the Desert Resort. Later, it was shown guarding the Dark Stone along with Clay's other Pokémon while being spied on by the Shadow Triad. Later, it was used to battle Black in a Gym battle and tied with his Nite. During the battle with the Shadow Triad, it teamed up with Elesa's Pokémon to protect the Dark Stone. At the League, Excadrill helped face Team Plasma.
Krokorok is Clay's second known Pokémon. It was first seen guarding the Dark Stone along with Clay's other Pokémon while being spied on by the Shadow Triad. Later, it was used to battle Black in a Gym battle and was defeated by his Costa.
Palpitoad is Clay's third known Pokémon. It was first seen guarding the Dark Stone along with Clay's other Pokémon while being spied on by the Shadow Triad. Later, it was used to battle Black in a Gym battle and tied with his Musha.