My theory is that Alois tries to hide his pain, によって being a cruel person towards the others in the Trancy household (by hurting Hannah, etc.).
But as the season progresses, he begins to like Claude もっと見る than allowed. He totally forgets that his butler is only nice to him because of the contract.
All that Alois ever wanted was to have a friend like Luka again. After all what has happened to him, he feels lonely and wants Claude to stay によって his side. But a demon has no human feelings. It's normal for Claude to be disgusted によって 発言しました feelings, so he kills Alois because his soul ロスト its taste によって declaring...

I have no idea... what goes through your mind.

"...There's so much I want to say, but I might end up hurting あなた again. "

You meant what あなた said, didn't you? But あなた apologized anyway.

"Whenever I call.." he continued, "All あなた say is 'uh-huh', 'yeah', または 'alright'... if there's something あなた want to tell me, then say it!"

If あなた meant what あなた said, don't say your sorry.

"I don't know whats going on in your head!"

"I'm sorry..." I sniffled, stopping in place. I pressed my nearly アナと雪の女王 gloves onto my eyes to stop the tears from flowing. To stop the emotions from gushing. To stop the time from ticking....

"Lord Sesshomaru-sama..." Jaken mumbled, lifting his feeble, green hand to his master's shoulder. Sesshomaru stared at Rin with his cold eyes of a shark. The young black-haried girl, freezing in the gusts of the early winter wind lay lifeless in his arms.
"Rin," The Lord began, "Why were あなた foolish enough to stand in the crossfire of the battle?"
Her dead body did not answer. A river of deep red blood gushed from the side of her mouth.
"You brought this upon yourself."
Rin's permanently shocked face grew pale.
"I have no sympathy for you." Sesshomaru huffed, lifting his nose in the air a bit. "Human...