Istredd's brushed off concerns about his safety from others because he trusts Lucifer and he doesn't particularly like seeming like he can't handle himself. Something Lucifer is well aware of. But his conversations with them are different than his conversations with Lucifer, which can be more direct and honest. Outsider opinions don't matter.

Fortify how? Defensive shields both physical and mental? I'll look some things up, see what we can test out. Magic isn't perfect right away after all. They can go through a few options. Istredd considers it important to try if it puts Lucifer more at ease.

I'd like if we could be together without your fear of breaking me. So you can relax for once. He picks up a fiction book and makes a face, setting it to the side. It gives him a moment with his hand free to reach over and cup Lucifer's cheek, caressing his jaw gently, before moving on.