"Each character gets +3 strength while it is standing."

Does this count for all characters in play including opponents'?

Thanks

Indeed. Unless the card specifies further (with the wording "characters you control" or "your characters"), it refers to all characters in play, including those of opponents.

That seemed most logical to me. Thank you very much.

I like this card a lot. Works really well in decks where you have people who can attack/defend without kneeling. It's also a good counter to burn.

I hadn't thought of it that way. Wow.