Daniel's quest is to bring peace to Eden by uniting humans and monsters. Needless to say, he's got a lot of work cut out for him. Not only does he have to persuade humans AND monsters to give peace a fair chance, but they ALSO have to be willing to change their ways: for the monsters, to see humans as equals instead of breeding tools; for the humans, to see monsters as allies instead of threats.
That aside, Clover raised a cold statement in Act VI, where she said how the Giant Butterflies have nothing to offer Eden.
While this statement is very untrue (as I'll explain below), it does raise a fair question:
What will monsters offer the world if they, their races, and humans unite? A big question that always comes up in terms of agreement or coexistence is, "What's in it for us?" Peace is wonderful and everyone loves it, but knowing how people are, they'll always look for that additional sweet benefit. So, how can the humans benefit from being friends with monsters? How can monsters contribute their skills to help make Daniel's dream of coexistence possible?
Needless to say, a full list of all the monsters in Eden isn't currently possible, but given that Daniel does have some allies as of Act XI, we can list off a few notable ones.
1st - Ant Girls. Being excellent diggers and miners, ant girls are incredibly strong, which could make them good fighters, body guards, or dutiful workers that involve heavy lifting. Their saliva also makes for a good pain reliever. Whether the saliva has to be in their mouth in order to work is unknown. Additionally, because most of them are hive-minded, they have a great sense of attachment and affection for those whom they consider family. With an ant girl, you'll have a companion who is loyal, hardworking, and affectionate. And though they can only squeak, they have a very sophisticated vocabulary, so each word is meaningful and worth hearing.
2nd - Giant Butterflies. Contrary to what Clover said in Act VI, Giant Butterflies actually have a lot to offer Eden. For one, they are excellent crafters and builders. The butterflies of Flairwood have designed clothes, crafted their homes and furniture, and are capable of making ointments and creams. They have an eye for detail and beauty, which makes them excellent designers and builders, and because they can fly, they can reach heights that other races can't, which would undoubtedly assist in construction.
Additionally, they appear to be good scavengers, seeing as they mostly feast on beetles and other insects. They know where to look when it comes to food and ingredients for some medicines. In all, Giant Butterflies, if given the chance, can be wonderful members of Daniel's new world.
3rd - Witches. When it comes down to it, the potential witches have to offer Eden is endless. First and foremost, they have, perhaps, the widest array of skills and knowledge when it comes to magic — not including Twilight or Aeon. Spells, hexes, jinxes, curses, potions, relics, magical enhancements, witches can provide a lot to humans and other monster races. They can be good with business, medicine, protection, construction, etc. They understand the magical Ether and can make good teachers, especially as most of them live very long lives. It's no wonder Daniel was so determined to get Charlotte and the witches of Rystone on his side. In a world like Eden, magic users are invaluable, and given the fact that witches can be quite dangerous, you want to know which ones are trustworthy.
4th - Centaurs. When it comes to speed, there is no other monster class that outmatches the noble centaur. They can cover more ground and reach their destination faster than any horse. They make good couriers, so they're good with delivering information, mail, small loads, etc. They could even help train people to improve their own speed, such as in athletics, physical fitness, or militia.
5th - Harpies. Kind, loving, nurturing, harpies strive to be good wives and mothers to their husbands and children. They're gifted healers and shaman, specializing in magic of the spirit and soul, and thus can help in places where conventional medicine cannot. They could make good therapists, psychologists, and can set people back on the right path and lead better lives. Additionally, being able to fly means they can scout for trouble or deliver messages or cargo.
6th - Elves. The strongest, most accurate archers in Eden, elves make for superb hunters, scouts, and snipers. Their skills with the bow is unmatched, especially since their bows are specially made to be three-times more taut than regular bows. They have enhanced perception, can see in the dark, have razor sharp reflexes, and have fierce fighting spirits. Clover alone is proof of how helpful and noble elves can be; then again, she's in a league of her own given her prowess with a bow.
7th - Nixies. Nixies are master swimmers, thus their navigational skills would be helpful for sailors crossing the seas and lakes. Additionally, being able to breath both underwater and on land, nixies can help with fishing, aquatic life and research, and can teach others how to swim.
8th - Reptile Girls and Orcs. Skilled in combat from the moment they can stand, they make good soldiers, guards, and defenders. Their strength can make intensive labor much easier and can assist in training troops.
9th - Lycans. Skilled hunters, reasonably good fighters, fair mentality . . .
10th - Sand Wraiths. ???
11th - Arachne. ???
This is what I've gathered so far. Anyone who wishes to contribute, feel free to. The world of Eden gets bigger for every Act, so new information is always out there.