A possible back story could be that the Warforged was created as a tool for a powerful wizard. Over time, it absorbed magical knowledge from its master. After the wizard's untimely death, the Warforged, now free, decided to continue the study of magic on its own, using the knowledge it had gained. It wandered the land, seeking more magical secrets and ways to improve its skills.
You can start by thinking about its origin. For example, if it was created in a dwarven forge, it might have been exposed to dwarven rune magic which influenced its path to wizardry. Then consider its motivation. Maybe it wants to prove that Warforged can be more than just soldiers. It could also have a mentor figure, like an elven wizard who saw potential in it and guided it in the ways of magic.
First, think about your character's origin. Were they born in a small village or a big city? Then consider their family. Maybe they had a strict father or a loving mother. Also, important events in their past can shape the back story. For example, if they witnessed a great battle as a child, it could influence their view of the world.
A good DND back story can start with a simple concept like a tragic event in your character's past. For example, if your character is a wizard, maybe they accidentally caused a fire that destroyed their village. This gives a strong motivation for their actions, like a quest for redemption.
A Dragonborn might have a back story where they were born in a small, isolated clan. Their parents were fierce warriors who taught them the ways of combat from a young age. This Dragonborn grew up with a sense of loyalty to their clan, and as they got older, they set out to explore the wider world to prove their worth and bring honor to their clan. They might face challenges like hostile races and difficult terrains during their travels.
One great druid back story could be that the druid was born in a forest that was constantly under threat from loggers. As a child, they witnessed the destruction of their beloved forest home. This led them to study druidic magic to protect nature. They learned from an old hermit druid who taught them the ways of the wild. Eventually, they became a great protector of the forest, using their powers to fend off any who would harm it.
A Goliath's back story could be that they were exiled from their tribe. Maybe they broke an important tribal law, like failing to protect a sacred site during an attack. This led to them having to wander alone, facing many challenges and learning to rely on their own strength in the outside world.
To create an interesting DND Goliath back story, start with their family. Maybe their family was shamed in the tribe for some reason. So, the Goliath has to work hard to restore the family's honor. For example, if their father made a mistake in a battle long ago, the Goliath is now on a mission to win great battles to erase that stain.
A possible back story could be that the dragon was found as an egg by a powerful wizard. The wizard, having an interest in rare and powerful creatures, decided to raise the dragon. He used magic to influence the dragon's growth and trained it to be his loyal companion. Over time, the dragon learned to understand complex commands and even developed a bond with the wizard that allowed them to communicate telepathically.