We need to give the Krayfin time to figure out his own strength; Impossible Island can be that haven for him as he grows into his birthright power. I am sure Hiccup will want to visit once he returns from Nepenthe. You should wait for him by his house at Berk!
1- Wait for Hiccup at his house -One month later-
Hiccup
Wow. You had as big an adventure as I did! I trusted you, and you came through in a really big way. You even figured out what the Krayfin needed at the labyrinth without anyone to help you!
I wonder how much the Krayfin has grown on his own. I hope he's become a confident dragon. Come on, let's check up on him. Toothless and I will meet you at Impossible Island!
2- Go to Impossible Island
Hiccup
'Impossible Island' feels just like any other island, doesn't it bud? I wouldn't have guessed that this bland island hides a beautiful cenote secret. Toothless and I can't wait to see it!
Well, click on me and lead on, explorer!
3- Click on Hiccup and lead him to the cenote
Hiccup
Wow. Your descriptions did't do this place justice. This is unlike any place I've ever seen. Now,,, if I were a baby leviathan, where would I hide?
[animation]
Hiccup
Aha, here you are! Come on down, [your Viking's name] - you're lagging behind!
4- Glide down to the bridge
Hiccup
There, there, big guy... we're happy to see you too. I think he's outgrown the nickname of 'baby' Krayfin, and then some!
His new diet is agreeing with him! Ha ha. Don't be a stranger, [your Viking's name], you should come closer and click on him!