The contract is an agreement of sorts, that place a binding obligation between parties. Another anime in the same season throws the word contract around (Chunibio, love and other delusions), where even the relationship between the main characters is a "contract".
In the magical world of WCW, the contract does not need a physical (paper, etc) shape. Merely the agreement and binding of magical powers is enough.
So, lets examine some contracts in the anime:
Honoka, Evermillion and Ayaka: Evermillion and Ayaka have a contract. Ayaka pledges to defend Evermillion's host (Honoka), and Evermillion pledges to supply mana to Ayaka. The contract's benefits are seemingly endless mana to Ayaka, wound absorption (Honoka's wounds are transferred to Ayaka). Displeasing Evermillion (when Ayaka and Medusa merge, Ayaka loses the mana because she is no longer "pure") causes the contract to be suspended. There is a particularity of the contract shown in the last episode, but SPOILERS enough.
Ayaka and Medusa go into a contract of sorts when they merge.
Head Workshop Mage and the city: the city contract is almost an enchantment. The Mage bound to the city pledges to use his mana supply to protect the civilians and reconstruct the city. The workshop witches cannot work their magic if the head mage is out of mana. When Weekend's bomb goes off, Kazane's mana is completely drained off, and her contract is suspended, causing all workshop witches to lose their powers. It takes a absurd amount of mana to sign-bind-cast this contract, as its shown in the final episodes, but SPOILERS enough.
So:
Are there any benefits to a contract?
- There are benefits and drawbacks to contracts.
Is there a limit to how many contracts you make?
- There is no limit to the amount of contracts you can get, but you are still subject to conflitcs of interest (medusa and Ayaka's merge can be considered a contract too).
Can a contract be made with anything else besides a town or a person?
- Unknown, as it is not shown in the Anime.
