You can choose another player to help you in most battles. After the fight you can send a request to that player to be your friend. When a registered friend assists you, you will earn friend points. These can be used for draws for new warriors.
Souls
Save souls for powerful attacks against Bosses. Mixing up attack methods uses souls. If you run out of souls, you will lose the battle. Use souls carefully while travelling on the battlefield so they can be saved for Bosses. Attack as many enemies as possible. Fighting makes you stronger and helps you build your library of fighters. You will earn souls for each enemy you kill.
Spirits
Gold and Silver spirits can be found on the battlefield. Sell them for gold. Fusion spirits can allow a fighter to gain a lot of experience points.
Tiles
Battlefields feature colored tiles. If you land on one, any connected warriors in your party will get a boost in strength. Do this before a Boss fight to build up your troops. You can tap a single tile for a single attack. You do not have to make a connection between tiles to launch an attack. Tapping a single tile will trigger linked warriors in your party to strike against your enemy. When you select a direction to move, it will remove the weapon that direction is paired with. Consider this when moving around to avoid becoming stuck with a attack icons that are not linked to a fighter in your party.