Holt is the only person able to listen to opperetta’s voice live; because of his already wacky demeanor he is immune.
Opperetta was'nt aware of this however. One day holt caught her in the middle of practice in the catacombs. When she spotted him he put on this cheesy mind control act which freaked opperetta right the flip out. holt carried out the act for a lil longer (because he is socially inept and a doof) then he burst out laughing.
operetta was sooooo immaculately angry she let out a blood curdling falsetto note, stormed out, and ignored him for a month.
that didn't stop holt though; every time he saw her he let out his most korny pick up lines and amped up his game 100%. finally he cracked down operetta who at this point just felt sorry for him in a condescending yet affectionate way.
they became an item again annnd alll was welll in the catacombs.