Ghosting is a very useful skill to know when on the battlefield.
Ghosting is a method of hiding / protecting your troops from being killed if you are attacked by another player. While you can protect them using the bunker building within your castle, there is a rather limited number that can hide there and the bunker is completely useless for the battlefield events (BoC and BoG). So this is where ghosting comes in.
You would surely have noticed that when you send troops out gathering or attacking, they are removed from your rally spot. The same principle applies to rallies. When your troops are sent to a rally, they disappear from your rally spot (having gone to the rally host's castle). If you are the rally host, then the troops go into an (invisible) 'assembly area', which like the bunker, protects them from being attacked. The troops remain here until the rally timer countdown is completed (or the rally is cancelled), then they get sent out on the attack (or return to the rally spot).
So this can be used in our favour, to prevent troop death and wounding, therefore reduced troop healing, if we ghost our army when unbubbled. There are some factors to consider when doing it though ...
1. Your march size - rally spot level and military research will effect how many troops maximum you can put in your rally.
2. The number of marches you have - it is important to consider how many troops you have and how many marches you need to hide them in.
3. Your stamina - rallies on boss monsters require stamina, but won't break your bubble. Select a low level boss (1-3) as this will use far less stamina than ghosting on a big boss. It may be useful to bookmark this monster to allow several rallies to be quickly set up.
4. Your bubble - be aware that a rally using another players castle will firstly burst your bubble, and secondly, will alert the player (DarkQueen's dreaded red screen effect) and may alert their alliance of your presence and intent. They will be able to see power of the troops you are ghosting too. It is best to try and find an abandoned or un-allied castle to ghost against.
5. Alliance rallies - it is important to check your alliance rallies for time and boss level BEFORE joining. A 'true' rally will be set for no longer than 10 minutes maximum and with our keep levels are likely to be higher level and special monsters (not a zombie, redcap or Centaur, or another player).
ANY RALLY over 10 minutes or against a level 1-3 boss is most likely to be a ghosting rally. DO NOT JOIN! Your trail to join this rally will lead our enemies to the rally hosts location.
Lastly, but not least, if you have some spare time and spare stamina, check out your own ghosting abilities and skills. See how many marches you can hide your troops in. This will be an awesome skill to have and practice in the battlefields first. And please ask questions, if this is too complicated. I will be adding instructions to the Webpage with images that sadly can't be added here, that may help explain better.
Be safe my friends, stay bubbled and if you need to unbubbled, be ghostly.