a word made up from "rawr" and "grr"

you could say grawr
but "gawr" is better

"a" hydrodynamic, city pop, apex predator shark from the city of Atlantis, who mostly feeds on salman (salmon) and shrimp. She now lives on land playing video games, streaming and doing other shark stuff. Gawr Gura refuses to return to Atlantis due to its lack of French fries, and now spends her time as a Hololive EN member who entertains chumbuddies. She dislikes hot sand and likes food, PWWIE as well as the color blue.

(Keep loud stomak away from her at all costs)

A small shark that goes "A". She comes from the underwater kingdom Atlantis and is apparently 1,000 years old or so. She works with hololive-EN to live stream
She has a shark in a bubble named bloop and commonly calls her views chumbuds.

On Gawr is simply a variation of On God, or On Jah. On Gawr refers to the popular English Vtuber from Hololive, Gawr Gura.