You can only use each effect of "Chaos Betrayer" once per turn
The best time to play this card is when your opponent has spent a bunch of their resources on bringing out a big monster, like Saryuja Skull Dread or Borreload Dragon
If you control a non-Pendulum "Vaalmonica" monster, take 2 "Vaalmonica" Pendulum Monsters with different names from your Deck, add 1 of them to your hand, and add the other to your face-up Extra Deck
It adds new gameplay elements like Trap and Ritual Spell Cards, enhancing strategic depth, as well as Alignment a mechanic centred around elements where the stronger attribute completely destroys the opponent monster
So once you get this on the field, you can get rid of the most indestructible monsters your opponent might have
Any battle damage this card inflicts to your opponent is halved unless it has "Galaxy-Eyes Photon Dragon" as material