We have the elemental debuff, so why not make an elemental buff? Or will it be to op with the debuff.
Aegir -> nature def buff
Kashrek/Morgan Le Fay -> fire def buff
Guinevre -> purple def buff
Domitia -> holy/yellow def buff
Guardian Kong -> ice def buff
Was thinking atk buff
Like gravemaker, drake etc? Or higher? I think you nailed it with how OP it would be when coupled with the defence debuff