In our campaign we are currently in the sewers, with most of the rooms being corridors in which only 2 PC of medium size can stand side by side, and dire rats (small creatures) are commom enemies.
One common situation as you can imagine is that the 4 PCs are walking through a corridor in a 2x2 formation and then dire rats appear for combat.
As said in the dandwiki:
You can move through a square occupied by a friendly character, unless you are charging. When you move through a square occupied by a friendly character, that character doesn’t provide you with cover.
And also on this article:
Enemies block your movement (with some exceptions). You can move through (but not stop in) squares your allies occupy.
So you CAN move through allies but you can't stop on the same space as your ally is. Following that:
- If I am behind my ally on my turn, and directly in front of him there is a dire rat, can I move forward to attack the rat?
- If I can, do I then stay in front of my ally now or I move back to where I previously was?
- Can the rats do the same thing?