Dual-box(is this ok?)

[Eidolon]

i just wanted to hear it from the horses mouth :<

In this case, I would suggest putting in an in-game report and getting an answer back from a GM, as opposed to a community rep. It seems more likely you are worried for possible reprimand, but taking your word on good faith, this is the advised path I'd have for you.

[Niwashi]

Generally speaking, it's not accepted anywhere. I've never had someone admit to doing this, but I've been in at least two dungeon runs that went painfully slow. When I started watching the DPS, I noticed that one would move and attack while the other stood perfectly still. In both instances, one character would do a set rotation before ceasing to attack completely for several seconds.

I'm not sure that this is against the ToS since, as you said, they're legitimate characters. Still, I wouldn't risk it, especially if they're not on the same account. People often use this method to powerlevel and then sell characters later.

That's a different type of dual-boxing than the OP is talking about. If you have two different controllers (or two mouses/keyboards, whichever you're using) and alternating between controlling one character and then the other, that's both definitely allowed by the rules and definitely not allowed by most player parties, since, as you pointed out, it turns into each character standing idle half the time. It's perfectly permissible for solo play, though.

The OP has a single controller controlling multiple characters at the same time, and I'm not quite as confident that SE's rules would allow that or whether it would count as automating one of the two characters. (I think it would technically be allowed, but I'm not with SE so can't confirm their stance on it.)

Oh, and in either case, they have to be on different accounts. You can't be logged in more than once with the same account.

[TouchandFeel]

In pretty much every instance I have seen this question being answered for other games and other MMO's, their official answers were essentially as follows ...

Automating the control of multiple characters through a singular set of input devices is considered cheating and is against their ToS.

Controlling multiple characters each with their own set of input devices is not considered cheating and is not against their ToS but is often looked on negatively by the player-base.

While true for many other games, the above may not be true for FF14 but I would side with caution and assume it to be the case unless stated otherwise by an official source.

Also, if you are going into instances with other people that haven't agreed to allowing any form of multi-boxing before hand, don't be surprised if people become upset and try to kick you.