Ok, so I have an NPC bard who's actually a main villain pretending to be one of the good guys, and he currently is 13th with access to the following: Magic Circle, Planar Binding, Conjure Elemental. If he casts the circle at 4th level it will last 2 hours, giving him the time needed to conjure an invisible stalker using Conjure Elemental at 6th, then use Planar Binding at 7th to bind it for 30 days. Game balance aside, is there any reason this guy wouldn't use any day he doesn't plan on adventuring to keep a posse of Invisible Stalkers at his disposal? He could theoretically keep up to 30 stalkers bound in such a way if he used this every day.
Also, being a bard, he'll soon have at 14th the ability to select Planar Ally. From what I've read Planar Ally lets you summon a much wider range of creatures, and in this case I was thinking of using it bind Slaadi in a similar way. They have TERRIBLE Charisma saves, even the Death Slaadi would be easily bindable assuming he can get the names of some to call up. Is there any reason this wouldn't work in terms of game mechanics?
Also, being a bard, he'll soon have at 14th the ability to select Planar Ally. From what I've read Planar Ally lets you summon a much wider range of creatures, and in this case I was thinking of using it bind Slaadi in a similar way. They have TERRIBLE Charisma saves, even the Death Slaadi would be easily bindable assuming he can get the names of some to call up. Is there any reason this wouldn't work in terms of game mechanics?