is jujutsu kaisen episode 1 filler?

Yuji Itadori is a high school athlete with superhuman strength and a dying grandfather whose last words haunt him: 'Die surrounded by people.' When his occult club friends unseal a cursed finger at their school, attracting deadly curses, Yuji does the only thing that makes sense to him — he swallows the finger to gain the power to fight back. Ryomen Sukuna, the King of Curses, awakens inside him.

Jujutsu sorcerer Megumi Fushiguro arrives expecting a disaster and finds something unprecedented: a boy who can suppress Sukuna's consciousness through sheer willpower.