Skills

Skills are spirit abilities that drastically affect battles. Battle skills are used at will and consume SP, the bar that fills up in the lower right of a battle. Support skills are always in effect, but only your leader spirit and your chosen friend's spirit will activate their support skills.

Battle Skills
Battle skills can be activated by tapping on a spirit. This pauses the battle. If you have enough SP, the orange skill button will be lit up. After tapping it, applicable targets will be lit up on the field. Tapping a target activates the skills and subtracts the appropriate amount of SP. One necessary point of interest is that as soon as you activate the battle skill, the spirit casting it loses all Action Energy. Thus, it is most efficient to activate battle skills while the spirit is attacking or after you're certain it is already queued to attack. This way you don't lose any Action Energy.

Note that any actions that are already queued will occur before the skill activates. For example, if 2 of your spirits and an enemy spirit have full Action Energy Gauges within a second of each other, the first spirit will attack, queuing up the other 2 spirits. If you choose this time to activate a skill, the other 2 spirits will attack first, then your skill will resolve. This is important because, while the skill is still queued, Action Energy will continue to fill up; if another spirit fills up its gauge, its action will be queued up after the skill.

This means that skills that increase or decrease Action Energy may not work as intended; if an enemy spirit fills up its Action Energy Gauge before a skill would decrease it resolves, that skill will have no effect on the enemy; likewise, if your spirit nearly fills up its Action Energy Gauge, a skill that increases a spirit's Action Energy will appear to have no effect. Similarly, for skills that stop an enemy, the target can still attack after it has been stopped if its attack was queued up before your stop resolves.

Support Skills
Support skills confer some kind of global bonus that does not need to be activated. The first spirit in your party, the party leader, if you will, will activate its support skill, and the friend you choose to assist you will as well. If you decide not to choose a friend to assist, you will only get 1 support skill. If the leader spirit falls in battle, the spirit that replaces it from your reserves will activate its support skill. In other words, you will benefit from the support skill of any spirit in the leftmost lane during battle.