From Ex illis wiki
This article is only a summary. A cleaner, more detailed article will be posted later.
What are Spells?
Spells are actions shown in a blue frame.
Spells are one of many kinds of actions in Ex illis. Their effects tend to be incredibly varied, but what all spells have in common is the concentration needed to perform and the ability to speak up strange and varied spell casting formulas.
Some spells simply take effect automatically, but most of the worst kind of spells can be resisted. When it happens, you see the blue shield with a human shape in it as a symbol showing that the target resisted or that the spell simply failed. To calculate the chances a spell has to be resisted, the casting unit's Magic is compared to the enemy's appropriate Elemental Resistance using the AR 2.5.
Many spells have prolonged effects and add what we call a status effect. These kinds of effects are displayed just below the turn bar for the unit who is playing. When you open the unit view, the different status effects affecting the selected unit will be displayed in the bottom-right corner of the screen.
Status effects showing a white outer glow are Neutral statuses and cannot -most of the time- be cancelled.
Status effects showing a blue outer glow are Buffs (positive effects) and can be Dispelled by some enemies' skills.
Status effects showing a red outer glow are Debuffs (negative effects) and can be Cleansed by some friendly skills.
Every time an elemental ability damages a miniature, that miniature receives 10% increased damage from the following element for 1000 AcP. Whenever a new element is thrown at the miniature, its elemental chain is reset to that element and if it chained, the damage increases exponentially by 10% for each successful chain.