Mu Yanling is a blue aligned planeswalker and hydromancer from the Plane of Mountains and Seas, who is presumably human.

“Interesting … This mortal being seems to have been blessed with Qilin’s essence.” 

Amid the sounds of roaring beasts, a crushing wave devoured Mu Yanling’s village when she was a child, and she barely escaped with her life. By pure chance, a wanderer named Li Shan was nearby. He saved Mu Yanling and took her in. He raised the girl as family after she lost her own, and his courage always made her feel safe. As they wandered together, she grew stronger, and resolved to be ready if another calamity struck.

One day, while Li Shan and Mu Yanling were traveling to visit the clan of Cloud Dream Lake, Li Shan suddenly collapsed. He was dead before Yanling could react. Paralyzed with grief, she could do nothing but hold his body and weep until she lost consciousness. But when she awoke, his body was gone! In spite of her sorrow and confusion, a spark of hope was kindled—was it possible he wasn’t really dead?

Yanling set off to search every corner of the world for some trace of her beloved mentor, from the Eternal Divided Realm in the south to the Dark Sea of Penglai in the north. She even ventured to the mysterious Ten Wizards Mountain seeking the secrets of time magic that might undo the tragedies of her life. She will not give up her search until she finds the truth of what happened to Li Shan, whether he is alive or dead.

In Dungeons & Dragons

Mu Yanling’s specialty is hydromancy: the power to control masses of water to do her bidding. Selecting spells that control water don’t give her (not any character who does) additional benefits. So we figure out a re-creation of the Spell Thematics feat from 3rd Edition to work out fine as a simple 5e narrative variant for spellcasters.

SPELL THEMATICS
Spellcasting variant

Choose a theme for your spellcasting, such as «ice» or «fire» or «screaming skulls» (or in this case, «water»). All spells you cast have this theme in the manifestation of their effects, although this does not actually change the spell in any way. You cannot use this feat to make your spell manifestations invisible, and it never causes your spells to deal more damage because of the visual change. For example, if your theme is «fire,» then your magic missile spell might appear to produce bolts of fire, although the bolts still are a force effect and cause normal damage, not fire damage. If your theme is «screaming skulls,» your fireball might manifest as a small screaming skull that impacts the target and explodes into a fiery ball that momentarily resembles a 20-foot-radius burning skull, although it causes damage exactly like a standard fireball (and doesn’t cause any sonic damage, despite the screaming of the skull).

Have you played a themed wizard before? Or maybe a cleric or druid? How did their spells look like?