I am pretty sure this isn't very possible. I have seen gremlins and devilities on the same levels as eachother and they don't attck eachother. This makes no sense since they are demons meaning they are probably hostile to everything and gremlins HATE shadow.... Siriusly the only treaty between monsters are gremlins and constructs and undead and fiends.
Isn't it rather odd to how every family of monsters are frendly to eachother?
One of the missions state that gremlins contract out weapons design to devilite engineering firms (thus ironically making their culture seem even more like Dilbert, which is also about engineers). So the two groups have a trade alliance, and will fight to protect it.
There are a lot of strange alliances, though. Such as Chromalisks and Jelly Cubes. The former should want to eat the latter ...
I thought Gremlins outsource their office jobs to Devilites. Devilites are basically office workers anyways.
Don't you think, that making a complex interacting system between them is unnecessary? Excluding healers, no one mob is interacting with each other, if one mob spotted you, it will attack, independently to any condition (except HP). The open-world games are the only place for such system. Spiral Knights is arcadish, combat oriented game.
so far the only example of actual friendly fire we have ( trojans and rocket puppies dont count) are lichen fights (god knows how they start, but i've seen them). which i dont really understand, lol.
Gremlins try to chop down trees right? There's a few missions that say gremlins start chopping down trees so knights have to defend nature. What I'm thinking is that gremlins make paper out of trees and then give it to the devilites so they can continue business, since they do need paper, and in exchange the devilites offer them silkwings to heal their wounded. Then the gremlins decided to make healing class gremlins, and then the devilites ra out of paper, so they offered another trade, they wanted to become allies. Since they do both have common goals, destroy the knights. Since all the other monsters(except a few, like Nick because he's a impostocube yet he made the game) don't have brains and are dumb, they can't join because they can't write a simple thing like "I hereby join this alliance to destroy Haven and knights." So theres my explanation, and the 4 bosses can't join because,
1. Snarbolax is close to extinction because of rabies and people hunting for his Snarbostuffing.
2. Jelly King is being endlessly slaughtered every time he reforms as a cube because people want sealed swords and antiguas and jelly for breakfast.
3. Roarmulus Twins are being repaired constantly because knights keep destroying it with their divine avengers.
4. Vanaduke is busy defending his castle from CTR VH Blitz Needle invasions.
(Extra) 5. Impostocube is busy defending his precious monis from evil thiefs.
(Extra) 6. Soul Jelly is busy hiding in bushes to avoid getting caught and having his precious valuable unknown loot taken.
There is my explanation. Wait, shouldn't this go in lore?
Maybe for now they're all just teaming up to take down the Spiral Order, but they're failing. It's why they teamed up. :P Once we're all gone they'll go back to playing Lockdown with each other. And all the gremlin Demo's can go back to their precious Blast Network.
Ice jellies can freeze each other and also any other monster.
Trojans and Lumbers and Rocket Puppies hate everyone. Gremlins want to destroy lumbers, and Maulos wants to freeze everything.
They all see the Spiral Order as a great threat to them all, so they all formed a alliance together.
I have only seen menders around devilites out side of arenas (those don't count). My theory is gremlins and devilites are putting their grudges under the tabel to deal with the invaders.