Is there anything in the rules that states that when marshalling (Characters, locations or attachments) that I have to put those cards into control under my command?

If I want to pay for a character or location and put it into play with my opponent, is that against the rules?

This seems to be acceptable for attachments - some "negative" attachments do not necessarily say attach to an opponents character / location

thanks

Even an attachment played on your opponent's charcter is 'under your command' and under your control (who triggers Sun Stroke?). The negative attachments that specifically say 'attach to an opponent's character' are restricting what you can do with them, not enabling you to do something you couldn't normally. You can play attachments on any characters on the board, provided you meet other restrictions, but you will control that card.

However, attachments cannot be attached to non-characters unless they specifically specify otherwise. That means you cannot put an attachment that doesn't specify "attach to a location" onto a location.

Thanks Istaril - but Attachments weren't really the issue

Is there a game restriction that says I cannot pay to marshal character or location and place it on my opponents side of the board

Given that I would still control the card the issue is probably a mute point

Well.. "side of the board" is not really a game term except as it pertains to who controls a card. I could marshall my character across the street, if I were so inclined, but as long as he'd be a character I controlled, all his text would be read from my perspective, I could chose him for claim/participating in challenges, etc.

If I want to pay for a character or location and put it into play with my opponent, is that against the rules?

The only possible way for one of your cards to be "with (your) opponent" is for your opponent to take control of that card. You control all cards you own unless an effect specifically says otherwise. Since there is nothing in the rules that specifically says a card can change control when it is Marshalled, you cannot give a card to another player by Marshalling it. Or, to answer your question directly, "Yes, it is against the rules to pay for a character or location (or attachment) and put it into play 'with' (ie, under the control of) your opponent."

You need a specific card effect to give control of a card to another player.

Specific cards effect like the Honor Guards in each of the starter decks.