DND_Reborn
The High Aldwin
First off, thanks for the reply. I know it is a lot to digest sometimes (at least, it feels that way to me LOL!).

But as written it is a discrete activity on your turn--that is when you get to move. In order to get an actual "break" in your movement, you need to take some form of action. So, a PC can move, attack, and continue moving or move, open a door, and continue moving, etc. but you need an action of some kind.
The part that is bolded is what I don't agree with. If the rogue stops, and then continues moving without doing an attack, he didn't really "stop his movement"--he continued it. With your interpretation, the rogue is always guaranteed an attack with advantage--which is the same as flanking. shrug
I don't think the orc getting an OA via marking would really stop such tactics, since as well PCs get to use them against other creatures, but I could be wrong.
With your ruling, the only thing that would be good would be to hold the reaction to get an OA as the fighter passes, but if there is room to move he can move into the rear position and never pass through the orc's reach until that square--so no OA for that then.
And now the orc as either to change its facing or allow the fighter to attack with advantage. Now, this is true only in this case. In other cases with your idea of the rear "leaving your reach" the orc might get an OA. It just depends. It still doesn't make sense to me to allow an OA when some is moving behind you, but you see it that way so okay.
I'm not here to try to change your mind. 
I do think limiting the advantage to few allies helps balance out flanking (however it is achieved) so I am totally onboard with that. Facing does help with "hiding" for rogues, so I, too, am all for that.
FWIW, we already use facing in our VTT and the rear advantage mechanic. For flanking, you have to use your bonus action to grant your ally advantage on their next attack (not all of them, just the next one). Those have balanced it out well for us, but thanks again for providing more detail. Much appreciated.
I am not thrilled with movement in 5E, either.The thing is, the way the rules for movement in 5e are written, it isn’t a discrete activity with a start and an end. It’s a resource you expend to change your character’s position. It’s actually something I find to be a bit of a flaw in the way the Facing rules are written, since short of a creature running out of movement, there’s no mechanism in the rules to indicate when they’ve “ended their move.” My interpretation is that, when a creature stops moving, you can use a reaction to change facing. If the rogue spends 15 feet of movement to get behind the orc and then stops, the orc has an opportunity to use a reaction change facing. The can either take that reaction, in which case it will turn around and then the rogue can spend 15 more feet of movement to get behind the orc again and attack, or the orc can not take that reaction, in which case the rogue will simply stay where they are and attack. Either way, the rogue can attack the orc with advantage.
With marking though, (assuming the orc has made a melee attack against the rogue since its last turn), the orc can at least make an opportunity attack against the rogue - with advantage - when they try to move behind its back, making this rather silly tactic no longer viable.
Now, you may not agree with my interpretation of the rules, and that’s fine. But that is how I interpret them.

But as written it is a discrete activity on your turn--that is when you get to move. In order to get an actual "break" in your movement, you need to take some form of action. So, a PC can move, attack, and continue moving or move, open a door, and continue moving, etc. but you need an action of some kind.
The part that is bolded is what I don't agree with. If the rogue stops, and then continues moving without doing an attack, he didn't really "stop his movement"--he continued it. With your interpretation, the rogue is always guaranteed an attack with advantage--which is the same as flanking. shrug
I don't think the orc getting an OA via marking would really stop such tactics, since as well PCs get to use them against other creatures, but I could be wrong.
Well, it didn't face the fighter, it put the fighter on its side (yellow) so the fighter was no longer in the rear (red). Anyway, I wouldn't say it made an error because one foe or the other will be at its back and it has no way of "knowing" who is fighter or rogue or whatever, so it moved to try to position itself to the current threat after the fighter moved.I would say the orc made a bit of a tactical error by using its reaction to turn and face the fighter in fig. 2. By doing so, it has exposed its back to the rogue, which the rogue exploits for advantage in fig. 3. The orc can see that there are two opponents poised to flank it, so it knows one way or another, one of them will be able to get behind it and exploit its blind spot. That means the orc has to decide which opponent it’s going to allow to get at its back. Now, maybe if the fighter has multiple attacks it would be better to expose its back to the rogue, but if not, it’s probably smarter to let the fighter attack its back in order to keep an eye on the rogue. Especially since doing so would free up it’s reaction to make an opportunity attack against the fighter as they pass, which would also mark the fighter until the end of the orc’s next turn, giving the orc more options to punish the fighter’s next move.
With your ruling, the only thing that would be good would be to hold the reaction to get an OA as the fighter passes, but if there is room to move he can move into the rear position and never pass through the orc's reach until that square--so no OA for that then.
And now the orc as either to change its facing or allow the fighter to attack with advantage. Now, this is true only in this case. In other cases with your idea of the rear "leaving your reach" the orc might get an OA. It just depends. It still doesn't make sense to me to allow an OA when some is moving behind you, but you see it that way so okay.


Several more decision points to arrive at basically the same thing isn't a good thing IMO, especially since 5E is supposed to be simpler when possible.but the former has several more decision points involved
Since it appeals to you, kudos!It gives the players (and me) more factors to consider in positioning our characters. More decision points, more need to try and anticipate your opponent’s moves. As you said, it limits one attacker to gaining advantage rather than both, which is a significant plus. It also makes hiding in combat a more viable option for rogues, which as a big rogue fan I appreciate.
I do think limiting the advantage to few allies helps balance out flanking (however it is achieved) so I am totally onboard with that. Facing does help with "hiding" for rogues, so I, too, am all for that.

FWIW, we already use facing in our VTT and the rear advantage mechanic. For flanking, you have to use your bonus action to grant your ally advantage on their next attack (not all of them, just the next one). Those have balanced it out well for us, but thanks again for providing more detail. Much appreciated.
