Deepolis has a very large number of clans, and the number grows every day. To found or join a clan, check out the clan tab at the top of your game page.
Here you can found your own clan, with a unique name and a tag. (Tags must have 2 special characters and 3 letters or numbers. Ex: =*EX1*=) (Note: Founding a clan costs 500,000 Cel.)
When you click this, it will bring up a blank page with a search bar. You can type in the tag of the clan you want to join (you don't have to enter the special characters, just the letters. Ex: EX1). It will bring up all relevant matches, with the name of the clan, what faction the clan is, etc. Most clans have more than one "branch", to allow multiple factions. When you find the branch of the clan you want to join, just click it and it will take you to the clan's page, where you can apply. (NOTE: Application costs 10,000 Cel. Most clans don't care if you fill out the application form.)
When you found or join a clan, the clan tab will change, and you will have more options:
This button will take you to your clan's page, where you can edit your clan't picture, edit the description, accept/send peace requests and war declarations, even change your clan's tag and name. This is accesible for normal players, but they can't edit it unless you give them the rights to.
Here you can view your members, give them rights (or take them away), accept new members, kick them out, and message them. This page is also assesible for normal players, but they can't edit it (grant/revoke rights, accept new members, kick members) unless you give them rights to.
Only accesible for people who have rights to it, such as the clan leader or co-leader, the treasury is a form of cel bank. Every night it takes a percentage of "tax" from your members, and deposits it in your treasury. You can edit the amount of tax taken (10% being the maximum) to your liking. You can also give cel payouts to your members. The payout amount is only limited by the amount of cel you have in your treasury. When you have enough cel in your treasury, you can expand your clan by adding a new Group. (This function is in the portal). By default, all clans have 1 group. When you add more than 1, a new screen will pop up upon accepting a member asking which group you want to assign them to.