The only thing I am wondering, is what exactly falls into large beast category. Do Jinchuuriki count, or it's just summons? Otherwise seems really lame, unless it's meant as a GNW ninja fighting against summon, which is quite specific and very purposeful, and it looses the necessity to use the ninja at all. Not sure if someone was too dense in making such skill (if it's against ONLY Summons like in GNW), or someone disliked Yamato that much which renders him useless as a support ninja for 1v1 battles.