A huge chunk of names have some kind of religious origin IRL; it's actually hard sometimes to find names that don't come from some kind of prominent religious figure, be it a prophet, saint, deity, angel, etc. Most people just use whatever they think sounds good and don't care where it comes from or what it originally meant. That's not necessarily a bad thing, but I'll agree that when it comes to well-known figures, especially from actively practiced religions (whether you are a follower of them or not, but perhaps more so if you're not), it's a good idea to at least understand your character's (or pet's or child's or whoever else's) namesake and know its significance. There is no one-size-fits-all answer to "Is this offensive?" because everyone--including people within that religion--will have a different opinion. If you do choose to name your character after a deity or other prominent figure, just be informed about it and be prepared for the possibility that yes, someone out there may find it disrespectful even if that was not your intention. But also know that this can happen with pretty much anything. If that makes you uncomfortable, just changing the name and saying you were inspired by a certain religious figure is also fine. Choosing names can be difficult but also lots of fun when you get into learning about all their various origins and connections. You'll see that all names have some sort of meaning, and many of them go totally unnoticed by most people. You name your kid "God", you're gonna get funny looks. But naming a character Hera, probably a lot less so. There are real-life people out there named Hera today.