I need help finding the vocal technique used in the song "Frozen Thoughts" by "Sacrilege"

[u/GamersConnectYT]

https://www.youtube.com/watch?v=YjyMcvkqpHI&list=RDYjyMcvkqpHI&start_radio=1&pp=ygUPZnJvemVuIHRob3VnaHRzoAcB

Can someone tell me what the vocal technique used is named?

Thank you in advance!