Kent may have judged Sanders too early.
From what happened and the mindset he was in when he ventured into the Underworld, killing the Thirteen Underworld Kings and Queens was justified.
Per what he wanted and how he was recieved, it was perfectly in his right to do what he did.
He went there with a reasonable request. He only wanted a single bone from the Abyssal Chaos Prince skeleton. However, the Thirteen Kings and Queens decided to ride their high horses and threatened him, saying he had to leave or they would kill him.
Sanders did not get angry. He offered something very valuable, something that all the Underworld Kings and Queens wanted. However, they tried to snatch it from him, using their authority over the Underworld to suppress him.
Sanders then snapped, and by the time he calmed down, they were already dead.
"I tried to warn you losers, but you wouldn't listen. Now I have offended the Underworld Empress and her minions."
