Register them as trademarks for associated products, e.g. clothing, mugs, jewelry, posters, etc. - which would require actually using them on such. Even before use, you could apply to do it today on the basis of a good faith intent to use by calling an Illinois licensed attorney. Call me or one of the other Illinois-licensed attorneys listed here.
www.burdlaw.com firstname.lastname@example.org or 618-462-3450
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
If you plan on putting this information on the shelf for use later, the only way you can protect them is to not tell anyone about them. Patent, No. Copyright and trademark will not help you with abstract ideas for a character.
Once the characters are integrated into a story or used on promotional merchandise then you can start thinking about copyright and trademark.
If you never plan on doing either of those things yourself, the person you sell the ideas to would be the one to do that.
Consult with an attorney on how you can market the ideas and prevent someone from stealing your ideas.
It is natural to think that you should be able, for example, to publish one or two pages including a drawing of each character, and underneath it their name and a description of each (in as much detail as possible)m, with a view towards obtaining copyright protection. However, only patents can protect "an idea" in the abstract, copyrights only protect the "expression" of the idea.
Below is a link to a publication from the U.S. copyright office which relates to comic strips and cartoons. It is analogous to your situation (children's books)
"[C]opyright protection does not, however, extend to the title or general theme for a cartoon or comic strip, the general idea or name for characters depicted, or their intangible attributes. Although the copyright law does not provide such protection, a character may be protected under aspects of state,
common, or trademark laws, and titles and names may sometimes be protected under state law doctrines or state and federal trademark laws."
As you can see, copyright protection at this early stage could be achieved if you were to draw a few comic strip type panels depicting the characters and their names and attributes, but you would not protect the names of the characters.
Protection via a service mark would be an option, but you say "may" use them at " later date" for business promotion purposes. Since trademark rights are gained through use, only, it would be premature to recommend seeking this protection and you would be ill-advised to waste your resources.
I believe my colleague said it best by telling you to sit on the ideas for now, until you have actually produced a work of authorship for which copyright registration might be sought or until you are close to or actually using the characters/likeness thereof in connection with advertising the services of a business.
Short Answer: Keep them confidential.
As my colleague points out, probably the best way to protect these characters in abstract and without weaving them into a product or service (trademark) or story or other original works (copyright) would be to keep them to yourself until you are ready. Good Luck.
The purpose of IP protection is to prevent your business taken away by a copy cat. If you don't have a business yet, there is nothing to protect. Consult with an attorney.
This is not a legal advice or solicitation, and does not create an attorney-client relationship. Consult with an attorney. I work for Cardinal Risk Mangement and Cardinal Intellectual Property, IP service companies, but not law firms. I also am the president of Vepachedu Educational Foundation Inc., which is a non profit educational foundation. I also write cultural and scientific compliations for the foundation. I also teach at Northwestern university as a guest lecturer. I also provide some pro-bono guidance on immigration and other issues through Indian American Bar Association. I also have a contract with Cardinal Law Group, a law firm, for IP projects. All this information is on my profile at Avvo and also at Linkedin. Any views/opinions expressed in any context are my personal views in individual capacity only, and do not represent the views and opinions of any firm, client, or anyone else, and is not sponsored or endorsed by them in any way.
Short answer, make a story with all your characters and keep it short (2 to 3 pages). To protect yourself, hire an illustrator or animator to make a story for your characters as a WORK MADE FOR HIRE. Spend more than $300 on an attorney to draft this between you and the visual artist to ensure all ideas, manifestations, story-lines, characters, or any and all other intellectual property produced during the Agreement are assigned and unconditionally owned by you. The visual artist will get paid and the proper thing to do is offer them CREDIT in the publication and promotion of the work(s) derived from the Agreement. Be clear on deadlines and budgets up front. You will probably spend about a grand on the visual artist. Go back to the lawyer who helped you write the Agreement and pay her or him to file the copyright. Please check out the Writer's Guild of America before you go on this journey!
No legal advice or research upon which one can rely is being provided here. The author assumes all inquiries on Avvo are hypothetical, or too general to give competent advice. The author strongly suggests all serious inquiries be taken to an attorney's office with the intent to hire competent counsel.