Flaming Sword: The second most powerful weapon you can wield. The best one is Erdrick's sword.
Getting Crap Past the Radar: In the first town, you can meet up with an ardent female admirer who will "tag along." If you spend a night while she's with you, the dialog strongly suggests you and the admirer had a night of wild sex. This can also happen while you are escorting Princess Lora. (In the GBC and mobile versions, you can actually spend the night at the inn with both of them in tow!)
Face–Heel Turn: Potentially. The Dragonlord offers the hero a chance to rule over the world alongside him at the end of the game. Most players just select no and get on with the battle, but if you accept, you get a Non-Standard Game Over (except in all subsequent rereleases where he wakes up in a town near the Big Bad's castle, where the innkeeper says that he had a Bad Dream).
Guide Dang It: Your name actually affects your base stats and stat growth.
Healing Hands: Heal and Healmore, learned at levels 3 and 17, respectively.
Heroic Mime: Averted, but only at the very end of the game; till then, it’s played straight.
Playing with Fire: Hurt and Hurtmore (called "Firebal" and "Firebane" in the GBC version, and translated as "Sizz" and "Sizzle" in modern localizations), learned at levels 4 and 19, respectively.
Schrödinger's Butterfly: From the SNES version onwards, if you accept the Dragonlord's offer that We Can Rule Together, the innkeeper tells him he woke up from a bad dream. If you accept again, it becomes this trope.
Final Boss: The Dragonlord is the primary target of the player and the last enemy that the player has to confront in the game. Defeating him will result in the Ball of Light being the drop item, which will make all the other enemies in the game disappear when the Hero returns home to complete the game.
Orcus on His Throne: The Dragonlord pretty much just sits in his castle all game and waits for you to come and kick his arse. Justified in that, by all appearances, he doesn't have to move; talking to townspeople makes it clear that he effectively rules the world already, and from his perspective you come out of nowhere.
Playing with Fire: He can cast Hurtmore/Firebane/Sizzle, as well as breathe fire in his true form.
Scaled Up: After the player defeats his mage form, he quickly takes on his real dragon persona before continuing the fight.
Sequential Boss: Unlike all the other enemies in the game, the Dragonlord has two phases to the fight. You first get a standard boss fight with him in sorcerer form, but after depleting his health in this form, a fake victory scenario will play out before the Dragonlord "reveals his true self" and starts a second phase.
Squishy Wizard: By the time they get to him, most players can kill his first form in three hits.
We Can Rule Together: The Dragonlord makes this offer to you when you confront him. Most players just select no and get on with the battle, but if you accept, you get a Non-Standard Game Over (except in all subsequent rereleases where he wakes up in a town near the Big Bad's castle, where the innkeeper says that he had a Bad Dream).