You are trying to track down Arthur, including Merlin's past self.

Caliburn: "Are you sure we should be doing this? We've been following the energy the Merlin of this era has been giving off. Are you sure Merlin is ready to confront her past? No pun intended."

"Well, we still have some time before the Chrono Coffin Merlin cast on XV and Dark Eve breaks. Besides, we're here to undo what went wrong. Besides, I'm the one doing this, not her. Maybe I can cause things to become less tense between them."

Caliburn: "Very well."

You saw an explosion in the distance and ran towards it. After a few minutes, you saw a crater in the ground and Merlin floating with Arthur, showing signs of fatigue.

Arthur: "Merlin, how are these things getting stronger?"

Past Merlin: "I don't know, but I'll protect you no matter what the cost, and that includes my life."

You took another step and Merlin sent an energy shot, which you deflected with Caliburn.

"But must it include your life."

Past Merlin: "Oh, you. What are you doing here?"

"I could ask you the same thing. Aren't you supposed to be with the other sins, trying to undo Elizabeth's curse? Or helping us end Chaos."

Arthur: "Merlin, what's he talking about?"

Merlin: "I have no reason to help you. Why should I? Just because things backfired on that one you're with doesn't mean it'll happen for me. I can do things right."

"At the very least, go back to your friends. They've been fighting without you, they need your help."

Merlin: "Is my future self too busy to do that herself?"

The Merlin you know teleported right next to yourself.

Merlin: "No, she's been trying to undo the massive mistake that cost her everything."

Caliburn: "How did you find us?"

Merlin: "I kinda figured Y/N might do something like this. Can't say I blame him though."

Arthur: "Another Merlin? Wait, are you from the future?"

Merlin: "Yes, I am. That was a guess? Well, don't matter at this point. How's Camelot?"

Arthur: "With the holy sword stolen, I had no way to protect everyone, so I had them evacuate to Liones for safety until I could get it back."

Merlin: "So, should the kingdom be destroyed, at the very least the people won't get caught in the devastation."

Arthur is shocked at hearing Merlin's words.

Merlin: "Merlin, this path you follow, that I followed. It will only bring back suffering on an unimaginable scale."

Past Merlin got fed up and fired an energy beam in defiance.

"This was going to turn out better in my head."

Merlin: "Which was before I came along. Alright then, guess I better give her a good spanking."

Arthur: "Merlin, both of you, please calm down. We don't have to fight. Let's all just talk."

Past Merlin refused to listen and attacked her future self. A fight began as the two Merlins are battling each other.

While this was happening, Arthur took a look at the other sword on your back and saw the handle.

Arthur: "That handle. I recognize it. There's only one sword that has it."

Caliburn: "Lad, I think it would be best to just reveal the truth."

Arthur looks around to see who said that as you grabbed Excalibur and revealed it.

Arthur: "The holy sword. You took it?"

"Plan A was to take it along with the bit of rock underneath it, but I was able to pull it out of its pedestal."

Arthur: "Why did you take it? Wait, does this have something to do with what your Merlin said?"

"Yeah. Apparently, your best plan for the demons is to rely on Excalibur and hope that it can take on the demons, but Merlin and I have unfortunate news for you pal: Even if you have the fight in you, you're still not ready. You tried to take back Camelot yourself. Only for you to die before you get resurrected."

Meanwhile, the Merlins are still fighting. However, Future Merlin's odds are much better due to having much more experience.

Merlin: "Listen to me. Chaos isn't the answer to filling the void in your heart."

Past Merlin: "Shut up!"

Current Merlin locked a ring around Future Merlin, but the latter summoned a barrage of energy orbs that struck both of them. They fell down and both you and Arthur come for them.

The Merlins got up, and the future one managed to stand.

Past Merlin: "What's your problem? You're me. Why are going against this?"

Merlin: "Because your desire, my old desire, cost me everything. You are short-sighted, petty, and don't think things all the way through."

Past Merlin looked away as you and Arthur arrive.

Merlin: "You want to know what happened to our friends in the future? They died. Escanor lost his life after fighting the Demon King, but everyone we cared about died because of Chaos."

Past Merlin has a look of horror from hearing the other's words.

Merlin: "It corrupted Arthur, went insane, and rendered the entire planet an uninhabitable wasteland. The world needed Merlin of the Seven Deadly Sins, and all they got was this lady."\

Merlin reached into her jacket and pulled out a picture of her and the other Sins that she made before tossing it to her past self.

Merlin: "Y/N, we got a few more things to do. Let's go."

You nodded and went over to your Merlin before she teleported yourselves away. Past Merlin looked at the picture that her future self tossed.

In the present, you and Merlin appeared in a place a few miles away from the Boar Hat Tavern.

"Merlin, I'm sorry. This wouldn't have happened if I hadn't gotten that idea."

Merlin: "Nothing to apologize for. This was something I wanted to do for a long time. Anyway, let's rest then we can finish what we came here to do."

"Alright."

Caliburn: "We should also figure out what to do with Arthur afterward. Camelot needs a strong king and Excalibur must return to its rightful owner, but that can wait till later."

After starting a fire, Merlin sat next to yourself and fell asleep on your shoulder. You smiled and rubbed her head.