Sodo and Copia both adored Aether. Sodo was really close to Aether since he was the one that would deal with his explosiveness even if Aether kept bullying him for his height. Copia loved Aether and was close to him because most Quintessence ghouls end up bonding with their Papa the most out of any other ghoul.

After Aether and Sunshine were taken away from the two, Sodo was more explosive than ever, he'd snap at the smallest things and overall couldn't stop pushing others away. Copia on the other hand kept to himself a lot, he never felt like talking to anyone else. Sodo and Copia ended up being each other's support system because of this. They both desperately missed Aether and both of them had a hard time accepting the new ghouls, you.

Sodo: "Stupid new ghouls…replacing Aether and Sunshine like that…why'd they have to go…"