Yes! We recommend you do this by setting up a separate Leanpub account for each pseudonym. To do this, enter your pen name or pseudonym when you create your account.
If you have already created an account, you can change your name to your pen name here: https://leanpub.com/user_dashboard/settings.
The name you enter for your account, and your profile image, will be displayed on various Leanpub web pages, including search results, and on landing pages for books, bundles, and courses.
Please note that we pay royalties via PayPal, and you can set multiple Leanpub accounts to pay to the same PayPal email address by configuring the PayPal email address for each of your Leanpub accounts.