From GEWar Manual
This page explains how battles are fought and how the battle result is calculated by the game.
This article is a stub. Help the GEWar wiki expanding it!
So what happens if you click the "attack" button?
If you want to attack a city you need to move an army there. As soon as your army arrived you can click the "attack" button appearing on the city page. If you have several armies outside the city you need to choose the army you want to attack with.
The first thing what happens if you attack is that GEWar will put your army against the smallest enemy army in the city you attack and show you troop number and hit points of both armies.
The battle itself is random so several attacks with same hit points will give different results but a result of attacking and defending army losing about same number of hit points is most probable. The winner of the battle will have an army that is smaller in troops but the rest will be more trained than before i.e. the experience factor will be higher.
If you (the attacking army) are killed, you can go back to the city screen and attack again if you have another army outside the city. Otherwise, just send a new army from a nearby city of yourself or your base. If the defending army is killed, the next weakest army of the city is brought up to face off with your attacking army. Once all of the defending armies are killed, you get the city! Be aware that the only army in the city now is your one little army (probably weakened from battle), so you should move additional armies in there as soon as you're able.
The battle algorithm of the game is the same for attacking armies standing outside cities or homebases or for attacking homebases itself. But note that you can't conquer a homebase, you can just kill the troops inside.