Well, usually in such fanfictions, Toothless might go crazy and start attacking everything in sight to protect or avenge Hiccup.
In many of these fanfics, Toothless goes on a rampage because he's so worried and angry about Hiccup's injury. He might even show new powers or behaviors that weren't seen before. It's a way for the story to add drama and excitement.
Chapter 515, "Dismantling A Structure", is the clearest early answer because it turns Damien's situation into a concrete plot event. The setup is Not the kind of quiet that came from peace, but the kind that..., but the pressure keeps building through Mist hung low between the trees, drifting through shattered trunks....
Chapter 519, "Provoking Them", is the clearest early answer because it turns Damien's situation into a concrete plot event. A useful checkpoint is the way the scene starts with The forest no longer felt calm. and follows through with Because now, he was ready to hunt something stronger..
Chapter 14, "The Regular Cast", is the clearest early answer because it turns Redwood Ridge's situation into a concrete plot event. A useful checkpoint is the way the scene starts with There is a convention among the camps surrounding Redwood Ridge. and follows through with The Great Xia Camp has also slightly regained some vitality..
Chapter 477, "Demanding Half The Stakes", is the clearest early answer because it turns Damien's situation into a concrete plot event. The chapter gives readers a real answer by opening on The courtyard was still echoing with disbelief over what had just... and ending on Haldric waited a few meters away, arms crossed, lips twitching in....
Chapter 520, "Storming The First Base", is the clearest early answer because it turns Damien's situation into a concrete plot event. The chapter gives readers a real answer by opening on Damien did not rush into the assault. and ending on He paused only briefly before stepping inside.. In story terms, the chapter closes with And this time, he would not arrive quietly.
Chapter 155, "Lone Ranger, Xing Valley Pass", is the clearest early answer because it pushes Wooden Forest into a new phase or setting. Early on, At the same time, a lush Wooden Forest stretching from west to east.... By the end, Though Xing Valley Pass is a slope, that's the general situation; the....
Chapter 109, "The Consequences of Being Too Clever", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. It opens with On the north side of Redwood Ridge, within the territory of the Lu... and closes on Though the Teng Jiao's eyes were shut, its nostrils exhaled white....
Chapter 38, "Revised: Chapter 38 Please Forgive Us for Not Accompanying You", is the clearest early answer because it turns Bone Whistle's situation into a concrete plot event. Early on, On the snowy night, the dense white trees pieced together the outline.... By the end, Wang Rui, Sun Xinzhu, what's going on, why are you attacking Shi....
Chapter 535, "Open Attack I", is the clearest early answer because the buildup finally cashes out in a real clash. It opens with Far beyond the reach of the Forest of Twin Disasters… Beyond the... and closes on At the barracks soldiers were already moving.. The key payoff is that the chapter closes with The battlefield ignited instantly., which gives the main cast a stronger narrative position and pushes the power growth onward.
Chapter 62, "Soul Capturing, Promoted to Intermediate", is the clearest early answer because it turns Wood Puppet Monster's situation into a concrete plot event. It opens with At this moment, the valley ground was littered with the fragmented... and closes on My head hurts so much..." "Ah.......