What is the meaning of の here? ‥ ‥ ‥‥‥‥‥‥‥‥ It's a monologue from the game. That's the role of in this sentence‥ ?

It is used to represent stuttering speech. 'No-noroi nado to...'.

Without the comma (pause-indicator) it would be more difficult to interpret it as a stutter.