This is a idea I got from the zero to hero story. What would happen if hiccup left with toothless and returned 10 years later?
I was flying on toothless when I saw berk my girlfriend the godess frey said let's go to berk. I said let's go home. We landed in the forest and they just went flying. I sat in the town hall. One man asked What can I get you mr... I said nightfury. He said ok mr nightfury what do you want? I said do you know where my father is? He asked what is his name? I said stoick the vast. He said he only had one son hiccup. That is my old name. He gasped and yelled get stoick! I said I can wait. Stoick came in 20 minutes later and I got up. I said hi stoick it's been too long. Stoick said who are you? I said I left 10 years ago dad. He said hiccup? That's not possible you were killed by a dragon. I said hold on. I blew a whistle and 10 seconds later a black dragon covered in armor with a girl that also had armor on and she got off the dragon and smiled at me. I said this is the dragon that I escaped on a decade ago. One man said what is it? I said a nightfury. They all ducked and I laughed and said why is it people always do that when I say toothless' species of dragon? One man came up and said hey hiccup so how fast is the nightfury? I smiled and said well fishlegs andI know it is you he is 100 mph. He said ok iI'll come back with the book later so we can fill out the pages on nightfury. Frey then came to me and said so when do you want to get married? I said 1 week. She said wait what about your dad? I said why do you think I came back? I came back for his blessing and to live here once again and not in asgard. She said shhhhhh someone might here you. I said they will find out. Mostly astrid. Frey said oh ya love triangle? I said no way I know you are the godess of love, war, etc . but only one on one marriages for me. She sighed and said it was worth a try. I said ok lets tell my dad most of the story. Then someone came another nightfury I said hey toothless your girlfriend is here! He came on a running. And toothless said hiccup stop teasing and she is my soon to be mate! That is the same thing. I smiled and nodded and said you 2 go to the spot. They flew off. I think she will want kids a day after our marriage. I said uhhh dad I um well the only reasons I came back is for your blessing of my marriage with the goddess frey and to live here in the mountin and have a family then die. Oh and be cheif when you retire. He said ok. I was kind of shocked and well expecting a yell or a face or something. I said ok a week until the marriage. He nodded. I said I have the rings and clothes coverd so just plan the cake and the people and all that. He asked oh and where have you lived for 10 years? I said oh um ...asgard. Stoick was shocked and said so does odin have a beard? I said no he looks like a 13 year old. But his other form yes. He said ok and thor? I said he looks like you. With short hair a short beard and a cape. (He loocks like thor from the movies). I said oh and loki wants me dead for um tricking him. Stoick laughed. I said oh and I might leave evry so often to fight drago bloodvist. Stoick widened his eyes and said drago? The man who tried to burn me? I nodded. Then a man dragon thing came and said hiccup drago is coming for you and berk! I said great how long? He said 2 weeks. I said ok dad prpare my wedding then prepare for war. I will try to destroy the first 10 ships. Stoick said um what is that and drago is com7ng?! I said he is half man half dragon amd his name is dragon and yes drago is coming. I will have to call in the hell boys. I said dragon get the hell boys from asgard. In frey's room drunk. He nodded and flew up into a portal.