User blog comment:Burniez/Shusui OE Unit Idea/@comment-27362456-20161008173038

His leader skill should boost HP by at least 50% as it's standard for OE units. Also since he brings so much power to the battlefield I assume he has high Atk, but low HP and Def. So maybe for SP skill 30% boost to HP is better or 20% boost to HP & Def.