Fierce meaning 'extreme, tremendous, intense' would be 凄まじい /su sa ma jii/.
In sense of 'violent, ferocious' you can use 激しい /ha ge shii/ and 獰猛 /dou mou/.
激しい Hageshii
You may say 'araarashii,' written: 荒々しい
府県 /fu ken/ mean prefecture in Japanese.
it means sasaki in Japanese
Hot and fierce in french which is its origin.
激しい Hageshii
soe de no
They were the samurai, warriors pledged to fight for their feudal masters.
Fierce destructive
It means fierce
An animal, fierce creature, with long claws and sharp teeth. It fears nothing [ Wolverine ]
You may say 'araarashii,' written: 荒々しい
Small But fierce
Fierce is mean, brutal, vicious, desire to fight
ferox - fierce, ferocious
It means fierce one
Fierce or brave