The premise for my Japan-ish campaign is as follows;
The PCs stumble across a plot by an exiled Shogun who tried to overthrow the emperor to awaken and control kaiju in order to use their power to take over the empire. The kaiju are awakened one by one as awakening one weakens the seals on the more powerful ones. To stop the the PCs are each granted a magatama and sent on a quest to collect what is essentially magical giant robots in the shape of animals. Individually they can take down the minor kaiju but to defeat the largest, Mogaru, they need to find all of them to merge them into the Beat Lord.
Here is my problem; The PCs are supposed to collect them one by one with kaiju fights in between. Is there a way to make it so that they don't try to solve every non-kaiju problem with giant robots? There are plenty of Oni (think putties)and Oni generals (think Goldar) that are around to be defeated with good ole fashioned class features but what if they just go "lets just summon the giant robot we have to handle it? Sure the entire village will be destroyed but the oni won't wake anymore kaiju."?
Should I put a 'daily limit' on robot time? Would they clue in that giant robots is like nuking a platoon?
Give the Giant Robot X number of total rounds of use. Once those rounds are gone, their gone & it becomes just so much statuary.
Just to clarify, I'm using The Mecha Compendium for basics on how the Beast Lord robots work with tweaking to make Beast Lord comparable in power to Mogaru.
I took a second look and it appears that the original stats for the Beast Lords gives them full AI and thus class levels. Perhaps they don't want to fight anything but kaiju?
What's an appropriate time limit that's short enough to not abuse but long enough to defeat Mogaru?
Actually, as a riff on both my idea & yours, give the Beast Lord robots X number of 'total' rounds of activity, say a few minutes worth, but for phlebotinum reasons, time spent fighting Kaiju don't count against that limit. Basically, Kaiju frequently give off 'strange energies' which somehow manage to 'recharge' the Beast Lord robot's 'batteries'.
That way, the amount of time left doesn't really affect what you want them to use the Giant Robot for, but if they jack around wasting it on stuff they should be able to deal with themselves they find themselves S.O.L...
You could consider it two pools: one pool for general use (5 rounds ever or per day) and one pool for Kaiju Battles (5 rounds then 1 round rebooting repeating) that gets pooled together per robot that becomes merged.
Then, when they merge together, they could give OTHER synergistic bonuses to Voltron. The bonuses are unique compared to the robots that go into Voltron, but pool together to the whole. So if one robot runs 5 rounds a day, and another one runs for 3, then merged together they run for 8.
You said something about different animals being put together, so it would make sence that they would have different specialties. Maybe the Bird robot would give perception bonus and attack bonus, while the bull would give strength bonus and HP, while the lion would...
Make them no better than level-equivalent summons by themselves, but pooled together could be really interesting. Consider Digi-mon, Voltron, and Power Rangers as inspiration.
Don't really know what I'm talking about, but it seems thematically cool.
I like the idea that they react to 'kaiju energy' would give them a believable power source and makes the magatama sort of a kaiju detector if they light up in response to the kaiju energy.
The general idea was that the Beast Guardians gain it's caller's feats, BAB, caster levels, saves, ect and the combined Beast Lord was effectively a gestalt of the party. So if the Wizard commands the Eagle it would have it's own arsenal but in addition would gain the wizards spells for it's spell slots and add them to the Beast Lord's spell slots.