Louis and his constant worry over Lestat in the books

“Lestat, don’t go on the stage tomorrow night,” he said. “Let the films and the book do what you want. But protect yourself. Let us come together and let us talk together. Let us have each other in this century the way we never did in the past. And I do mean all of us.” - The Vampire Lestat

Louis, the watcher, the patient one, was there on account of love pure and simple. The two had found each other only last night, and theirs had been an extraordinary reunion. Louis would go where Lestat led him. Louis would perish if Lestat perished. But their fears and hopes for this night were heartbreakingly human. - The Queen of the Damned

“Now we can go home,” he said.
Home. I smiled. I reached out and touched the graves on either side of me; I looked up again at the soft glow of the city lights against the ruffled clouds.
“You’re not going to leave us, are you?” he asked suddenly, voice sharpened with distress. - The Queen of the Damned

For a moment, I couldn’t understand the expression of horror on his face as he stared at me, or why he suddenly rose and came towards me and bent down and touched my face. Then I remembered. My sun-darkened skin.
“What have you done?” he whispered. He knelt down and looked up at me, resting his hand lightly on my shoulder. Lovely intimacy, but I wasn’t going to admit it. I remained composed in the chair.
“It’s nothing,” I said, “it’s finished. I went into a desert place, I wanted to see what would happen…”
“You wanted to see what would happen?” He stood up, took a step back, and glared at me. “You meant to destroy yourself, didn’t you?” - The Tale of the Body Thief

I came towards him, planted my hands on his desk and looked into his face. “I was so sure you would understand this. And by the way, I wasn’t born a monster! I was a born a mortal child, the same as you. Stronger than you! More will to live than you! That was cruel of you to say.”
“I know. It was wrong. Sometimes you frighten me so badly I hurl sticks and stones at you. It’s foolish. I’m glad to see you, though I dread admitting it. I shiver at the thought that you might have really brought an end to yourself in the desert! I can’t bear the thought of existence now without you! You infuriate me! Why don’t you laugh at me? You’ve done it before.” - The Tale of the Body Thief

Dimly I thought I heard Louis’s gentle voice, protesting, pleading, arguing. I heard locks thrown, I heard nails going through wood. I heard Louis begging.
“For a while, just a little while.…” she said. “He is too powerful for us to do anything else. It is either that, or we do away with him.”
“No,” Louis cried. - Memnoch the Devil

I don’t live like our friend Louis, wandering from dusty corner to dusty corner, and then back to his flat in the Rue Royale when he’s convinced himself once more and for the thousandth time that no one can harm Lestat. - The Vampire Armand

All the faces were soon there, except for Louis and Rose and Viktor. But how could that be? I turned around. They stood only two feet away from me, huddled together, and down the pure whiteness of Louis’s face were two thin lines of blood tears. - Prince Lestat and the Realms of Atlantis

Louis had been gravely hurt that Lestat had gone off to meet Rhoshamandes alone. So Lestat had promised never to do such a thing again. - Prince Lestat and the Realms of Atlantis