I can't see if it has some some sort of bug. I want to add an ability like "WUG:Kokotoko enchants target permanent." and make him copy auras too, but i have the impession that it could create problems. I think it will be funny, especially in commander, to have some sort of gigantic aura that enchants everything, itself too. Tips?

PS it's my first card, here. Show mercy, please!

Welcome to Multiverse! I like your idea for a card, but I have multiple comments on different aspects of it. They are not meant to be negative, but it's hard to convey tone through text, so I thought I'd preface them with this statement.

• Imprint is no longer a keyword action. With the release of Scars of Mirrodin, it was changed to become an ability word, meaning that "imprint" no longer has any rules meaning. Therefore, the first ability is missing some words, and its reminder text is inaccurate. It should read "Imprint — : Reveal the top X cards of your library. Exile a noncreature, non-Aura enchantment card from among them with CMC X or less."

• Again because Imprint is now an ability word, the second ability can't refer to the "imprinted cards." It must instead refer to the "exiled cards."
• Being a copy of multiple things isn't feasible. I would instead have it read "~ has all abilities of all cards exiled with it." Generally, only activated abilities are copied, because having all static and characteristic-defining abilities can be a problem. However, I believe that most of the issues with this lie in gaining all abilities of creatures, which this specifically can't do, so it might not be a problem here. With this new wording, you no longer need to try and skirt the legend rule.
• This can't be an aura because it's a creature. You could, however, utterly change the second ability to allow this to fairly copy both creatures and Auras. What if it read "[Cost]: ~ becomes a copy of a card exiled with it, except its name is still ~ and it's still legendary. If ~ becomes an Aura this way, attach it to target permanent it could enchant." Then it doesn't get to be a copy of multiple things at a time, but you could remove the limitations on it copying creatures and Auras.

Don't worry, the last part of the comment was supposed to be a joke. I've got the same problem with the tone, like-i think-anybody on the web. Anyway,

-about the "Imprint": you're right! But, if it mentions just "the exiled cards", and it becomes a "Leyline of the Void", it will gain all the abilities of all the exiled cards, not just the imprinted ones. And not just the enchantments. Without looking at the absurde power level it will reach, I'm sure that, in that way, there must be some sort of bug. I can skip that making it refer to the "imprinted enchantments", maybe. I'll think about it.

-about the "gaining ability vs becoming a copy": Kokotoko was made to be a character in a story about nine immortal guys tryng to leave their plane by travelling to an obelisk at its center (something like The Holy Mountain + Interstellar + Land of the lost) and i found funny and a lot "tolkienish" that the more he learns, the more names it gains. But i can agree with you about the fact that it's a lot confusing, this way. I still think that being copy of multiple things it's weird but not totally out-of-the-rules. With your wording,do you think that it will be a problem to remove the "non creature" clause? I didn't played the Theros block, I know only the most famous cards.

-the fact that an Aura can't be a creature it's a rule? I think that making it enchant itself could be very tricky and funny!

I'm sorry for the rapes to the english language that i'm sure I had wrote (I'm open to critics about that, too), and thank you very much for the comments! I'll sure use your advices!

I've corrected the problems. I also made him a Wizard, because it was born as a Human. When I find a way to translate the story of the plane, I'll remove this card frome here and open a dedicated set page.

You can't refer to the imprint ability, since the word "imprint" is glorified flavor text. The way linked abilities work, you should be able to just refer to "the exiled cards" without including cards exiled through other means. I'd say "Imprint - , : Look at the top X cards of your library. You may exile a noncreature, non-Aura enchantment card from among them with converted mana cost X or less. Put the rest on the bottom of your in a random order. // ~ has all abilities of all cards exiled with it." (I also included some power level tweaks.)

If this refers to "the exiled cards" or "cards exiled with ~," then the two abilities are linked abilities. Cards exiled through other abilities this may gain will not add to the "imprint" total.

I totally forget the "put back" part! Thank you! I also decided to totally remove imprint: if i can not refer to it in a usefull way, better avoid to use it. It's an artifact ability, after all.

Thank you very much!

This should probably as part of the cost to activate its ability, or have some additional colored mana.