This system allow a back row character to support a front row character by buddy skills and a player to call a back row character up during a battle.
Buddy skills
Buddy skills are activated during a battle
A back row character's buddy skill become valid to help its buddy in a battle. The effect of those skills vary from increasing stats to restoring health. For details of skills, tap the link below.
This page explains what are skills and how field skills and buddy skills work.
Switching row
How to switch an active character to its buddy
Players can switch an active character to its buddy while in a battle by swiping a character icon down. There is no limit for switching and players can move a character between rows as many as they want.
Moving a character between rows helps players to select a character which has an element strong against enemies. Additionally, players can use Ninjutsus continuously since a back row character also charge chakra gauge.