Characters have abilities which strengthen themselves and different from enhancing which increase characters' stats. Abilities are used for enhancing same title characters and not for being used in a battle.
How to acquire abilities
By being enhanced with using a same title character as a material, the character can get abilities. However, acquiring abilities often fail to be done successfully.
Types of abilities
The effect of abilities varies from increasing stats, such as Attack Boost and Health Boost, to supporting characters in a battle, like Combination Critical Rate Boost and Reduce Skill Damage.
Where to see abilities
1. Open the character list
2. Select a character
3. Tap an icon at the right side of the screen
4. The description of the ability pops up
Please post all the abilities and their description like the Atk Boost ability and how much it boosts exactly