This section is incomplete. Please feel free to edit this section to add missing information and complete it.
Pokémon Ultra Sun
Dulse, along with Zossie, is encountered several times throughout the player's adventure in Alola, where they are investigating how Necrozma can be defeated. In learning about Pokémon battles, Dulse challenges the player to several battles throughout the course of the story.
Pokémon Ultra Moon
Dulse stays behind with Zossie in Ultra Megalopolis while Phyco and Soliera investigate Alola. He is first seen upon the player's arrival to Ultra Megalopolis, where he explains that Necrozma is at Megalo Tower.
After Necrozma is defeated, Dulse will gift a Poipole to the player in thanks.
"That was a most mysterious event... A festival to celebrate drawing forth one's full power..."
"Don't be silly... We are here to investigate and learn."
"Even with all of our technology, we cannot control the Blinding One's light... Thus we are left with no choice but to try to stop it by force! And yet it seems that the humans of this Alola can wield powerful auras."
"Calm yourself, Zossie. There is only one thing we are here to confirm. We must find someone strong enough to protect the Blinding One. Let us see if you might be the one!"
Upon being defeated:
"I don't understand!"
After being defeated:
"I see... So that is a Pokémon battle... We had tried to investigate what it meant to battle with Pokémon, but it is quite different when you do it yourself. At least it seems that the Poké Ball we tried to create has worked properly to capture us a Pokémon here in Alola. And I have seen for myself how strong you are, young Alolan Trainer."
"Trainer, you should know that this one here warps away if it is threatened in any way... And the holes that are torn open as a result invite dangerous beings into this world. But perhaps things will be all right as long as there are Trainers like you in Alola..."
"That girl should have nothing to do with our investigations, nor this Pokémon of hers... as long as no one is foolish enough to open a path that could lead here from Megalo Tower. Let us carry on, Zossie."
"Calm yourself, Zossie. Those must have been the Pokémon known as Sudowoodo. A most interesting Pokémon. I wish I could research them further. They must be mimicking plant life in an attempt to avoid their weakness—water."
"These Alolan Pokémon... They're all so unique. It's truly fascinating... But battling them is not easy."
"So I challenge you with one we are accustomed to...Poipole!"
Upon being defeated:
"So I have failed to understand Poipole!"
After being defeated:
"Our research is insufficient to define what it means to be a Pokémon Trainer... We'll never be able to stop Necrozma like this..."
"I will warn you now. Poipole cannot be found anywhere in Alola."
"I must research the reason for my defeat..."
"What are you suggesting? That it might be like the beautiful light our ancestors once saw?"
"Interesting... So this is what you call a tunnel... I would like to investigate it further if we only had the time to do so... Greetings, <player>. It seems your island challenge is going well?"
"It appears that my guess was correct: battling the Totem Pokémon, which are wrapped in aura, is having an effect on you as well."
"And those Z-Moves also envelop your ally Pokémon in aura, do they not? ...Are you able to fully control aura then?"
Regardless of player's response: "I suppose it does not matter to us either way. But once...long, long ago...our world was also awash in wondrous light, like the light of those Z-Moves that you can use..."
"Yes. We will be getting the aid of a scientist who is well educated in the ways of Pokémon. We will need his help to find ways we might use our technology to achieve our goals."
"That Ultra Beast just now... It came from the other end of an Ultra Wormhole... It is a being from another world. A world that you know as Ultra Space!"
"We came to the Alola region from another world by passing through an Ultra Wormhole. We came from a world of darkness, whose light was stolen by the one called Necrozma..."
"Our world is a world without light... The light was stolen by a creature known to us as Necrozma. A creature almost like an Ultra Beast. And someday it will come to steal the light of Alola as well...like an eclipse that never passes."
"So this is Tapu Village! We will need to investigate it quite thoroughly. According to the records we have left to us, it seems that this is where Necrozma battled against the tapu when it came to Alola long ago, hungering for its light."
"It may be the case that the power which came pouring out of the Ultra Wormhole at that time is what changes Pokémon's regular moves into Z-Moves. Such theories have been suggested..."
"Our ancestors were greedy, and they sought to control all of Necrozma's light... But what was the result of all that? They only hurt Necrozma, making it lose a part of itself and causing it to run wild and steal all the light it could find!"
"But that facility has reached its limit... And Necrozma hungers for light... That is why we came to Alola in hopes of finding a new method to defeat Necrozma. Yet.."
"It seems it will be a difficult mission for us, who are so new to Pokémon battling, to ever hope to defeat Necrozma."
"It is the custom of your people to have your Pokémon do battle if your goals are in conflict with those of another, isn't it? That is what we have learned during the course of our research."
"I may not be well practiced in Pokémon battle, but I will make you leave Cosmog to us. Show him/her your power, Poipole!"
Upon being defeated:
"Another defeat... I do not understand it!"
After being defeated:
"Even with all our technology, we cannot control the outcome of battle. This must be why we are unable to maintain perfect control over Necrozma..."
"Do not fear, Zossie."
"We can rely upon the strength of the Aether Foundation."
"We will use Cosmog and send formidable Pokémon Trainers through the Ultra Wormhole to battle and defeat Necrozma!"
"What is this?"
"That Lusamine! She is not defeating Necrozma for our sake, but for her own satisfaction?!"
"The machine that the scientist Colress helped develop with our technology... The machine that would restrain Necrozma... We were going to send it back to our world with someone strong enough to safely use it, but... she is going to use it for herself?!"
"The altar on Poni... The Pokémon that appears there is called the beast that devours the sun."
"Lusamine and Guzma... Do they not understand how strong Necrozma truly is? Or do they go to fight it, even knowing that?"
"I have a difficult time with such brilliance, but the light of Alola...is a good thing. The aura of your totems... And, yes, even the light of your Z-Powers. But now, if you'll excuse us..."
"Alola's light has been stolen by Necrozma... It is only a matter of time before all of Alola is wrapped in such darkness."
"You dare ask for our help now?!"
"Well...there is one thing I am curious about after witnessing that battle just now..."
"Necrozma seemed quite distracted by that bracelet you wear... that Z-Power Ring, or didn't you think so?"
"I see... So it is the Z-Crystals? And you... You were truly able to summon Solgaleo. Such an able Trainer... A Trainer like you might ride upon our Lunala to reach the world where Necrozma will be found. Yes, just as you people ride upon your Pokémon here in Alola."
"Perhaps you will be able to save Necrozma..."
If the player answers I'll do that to Zossie:
"We all share our Pokémon."
After defeating Necrozma at Megalo Tower:
"Impressive, human of Alola."
"While you were battling Necrozma in our Ultra Megalopolis, we were able to make some discoveries about the auras here in Alola."
"These...auras...must have been particularly strong at the trial locations. And the Z-Power for the Z-Moves... It is also similar to the auras of the Totem Pokémon. Both came to Alola as Necrozma's light!"
"You are such a powerful Trainer... Maybe you can return the light to Necrozma, without having it run wild."
"As a sign of thanks, we'll continue to share our Lunala with you. Use the Ultra Warp Ride to explore many new and different worlds! No doubt you will find amazing Pokémon."
"I think we will stay in Alola for a while. It is practically overflowing with Z-Power. It would be good for us to really experience life here. Maybe even do our own island challenge."
"There you are. The Ultra Beasts known as Blacephalon are wandering here in Poni Grove."
"...I seem to recall your being beside yourself with excitement, Zossie."
"We want to gather data that will help us protect the Ultra Beasts. If you would accept the Blacephalon as your partners, it would be of great assistance to us. Oh, and for the record, it seems there are at least three Blacephalon."
"With our skill level...we won't be much help in resolving anything that might involve a Pokémon battle."
After defeating the first Blacephalon:
"But it will now likely keep itself hidden for a while, and it won't attack other Pokémon. We can use this time to gather data and to work with the Aether Foundation to capture it."
"I would like to avoid these Ultra Beasts becoming a menace to Alola..."
After defeating the second Blacephalon:
"This will help us gather data we can use to protect the Ultra Beasts."
"Perhaps a day will come where the Ultra Beasts will live here in Alola as normal Pokémon."
"We are grateful for your help. I'm sure we will meet again..."
"Remain calm, Zossie. Human from the world of Alola. Necrozma has claimed Lunala's power and is now atop the Megalo Tower. The people here have all fled indoors to safety. They fear Necrozma will fly into another rage, as it did when that woman Lusamine appeared."
"Necrozma will reclaim its true power, now that it has stolen the light from another. But it cannot control that light, and so Necrozma only suffers more."
"We used the power of our technology to try to quiet Necrozma, while also using it to provide some small amount of light to ourselves."
"Both Necrozma and our own people have lived long years with a darkness that never should have been, living a life we did not wish for..."
"Human of Alola! Will you not stop Necrozma and bring the light back to our world...and Alola? Necrozma lies ahead. You will find it at the top of the Megalo Tower!"
"There's nothing that we here can do... We can no longer control it with our technology, and we certainly have no hope of defeating it in battle ourselves..."
"The light of Necrozma once filled our world. And it did not shine upon us alone. It gave energy to many, throughout Ultra Space."
"I do not know how long it will take, but someday in the distant future, perhaps we will also be able to bathe in such light again in our world... I am thankful to you, human of Alola. To you and the light of your Z-Crystals."
"The Necrozma that you managed to quiet... Yes, you might call it Ultra Necrozma. It shone with such blinding light, as it used to, only to lose that light all over again... It seems to have fled to Alola now. And your Lunala also returned home as soon as it was freed. I am grateful that you heard our request and fulfilled our dearest wishes."
"Then let me gift this Poipole to you. It is a sign of my gratitude to you. And also... to grant the wish Poipole itself seems to hold. Will you take Poipole with you?"
If the player answers, "Maybe next time":
"You can always return to get Poipole another time. Come back for it."
After explaining themselves, Dulse and Zossie were asked by Moon if they could take her and Sun back to Alola. Though Dulse refused, Lunala went to Sun and Moon, as it was already acquainted with them. Having no choice, Dulse allowed Zossie to go with Sun and Moon to Alola while he stayed behind. Dulse attempted to call Phyco and tell him about losing Lunala, but he was only able to get in contact with Soliera.
Dulse and Zossie used Lunala to travel through Ultra Space via Ultra Warp Ride. Due to Zossie's inexperience at piloting Lunala, she accidentally caused it to crash-land in the Ultra Deep Sea. After reuniting with Sun and Moon, Lunala left Dulse and Zossie to go back to its companions.