I am trying to figure out what is best for Blue Nomad King.
Unity book is suitable for support partners who rely on their 1st skills. For instance, Green Nomad King, Green Boar, Green Mr.Catfish, Red Bape,Red Nomad King, Red wolf, Blue Bape, Blue Sis Violence.Hurry up, Join in the events and forge your own artifacts!
Brutal Horn is suitable for partners with High SPD and ATK. For example, Green Desert Prince, Green God of Earth, Green Dragonman, Red Ursa Huntress and Red wolf. Blue Double-Blade Girl and Blue Black Shaman.
Brutal Seal is suitable for support partners with High HP. For example, Red Colonel, Red Guitarist, Red Drum Beater, Red Boar. Green Boar, Green Fierce Beast. Blue Colonel, Blue Fierce Beast.
Any suggestions?
Nice simple well put summary :). The Brutal Seal is most common for BNK, as they are often targeted by princes etc or splash damage this will help ensure they are as hard to kill as possible. Also to your own point above, the high HP partners benefit more than lower ones so BNK is perfect for this :).