Fighting Chant increases the player's ATK by (2% * Skill level) per party member on the same map. The player who has this skill is not counted for this skill. For example, a Taekwon with level 5 Fighting Chant will have their ATK increased by 100% if there are 10 party members NOT including the Taekwon him/herself. This increase is applied to the base ATK rate, not counting in any other buffs that may have increased ATK.
On iRO, this skill is localized as Kihop.