Defenders are charging out!

You've just attacked a dark nest or a castle, and while watching the battle, you notice that, close to the start of the fight, defenders "charged out".

When do defenders charge out?

Defenders will charge out if you end up with RNG troops only while the wall is not yet down: either because you sent RNG troops only from the start, or because the other troops you sent have all died while the wall was still up.

When this happens, the defenders change whichever formation they were supposed to be in to Infantry Phalanx. The battle report will state the original formation, but watch the battle or check the troop report: it won't match that formation (unless it was already Infantry Phalanx).

Use it or avoid it?

There's one case where forcing the defenders to charge out can be useful: if they have CAV and RNG troops only, but RNG on the frontline (meaning in Range Phalanx, Infantry Wedge, or Range Wedge). In this case, you can try sending RNG troops only: because they'll change their formation to Infantry Phalanx when charging out, but they don't have INF troops, they'll end up with CAV troops on the frontline, which you will counter with the RNG troops you sent.

In any other case though, and especially when the defenders have INF troops, you should avoid it, as your RNG troops will end up fighting their INF troops: you'll get countered. To avoid it, just send few CAV or INF troops, enough to have the wall down before they die. You'll get more chances to keep them alive by putting them behind your RNG troops (i.e. in Range Phalanx, Infantry Wedge, or Range Wedge).

Additional notes

• If you're attacking a castle blindly (i.e. without having a scout report), never send full RNG, as the target probably has INF troops waiting for you.
• Sending siege troops do not avoid the defenders to charge out. In other words, if you send RNG and SGE troops only, the defenders will still charge out.