How to update many documents in MongoDB, from a list of documents?

I have the following situation:

Documents to be saved:

[{character: "Elf", mana: 222}, {character: "Human", mana: 100}, { character: "Dwarf", mana: 0}]

And I have in my mongodb the following:

[{character: "Elf", mana: 150}, {character: "Human", mana: 50}, { character: "Dwarf", mana: 50}]

How is the best way to make an update so the characters get the proper values for their mana?

I cannot assume values to be more than a certain value, and may be I have another 50 more objects of different characters...

If I don't find the character in the database I want to Insert the new character, otherwise just update it.

I have being looking in the documentation but looks like updateMany is not what I am looking for, and update one by one looks expensive.

How can i do this properly?

via juan garcia