Puck can be described cute or adorable, thus his skin being pink around his cheeks. His fur is mostly grey with silver in certain spots (i.e. tip of the tail). His eyebrows are pretty small and rhombus-shaped. He also has a gold earring on his left ear. Sometimes, he has a purple bag round him.
Puck is generally a nice spirit. He is very happy and stays at Emilia's side to protect her, affectionately calling her "Lia". He goofs occasionally and gets along especially well with Beatrice. However, Puck's demeanor greatly changes in loops where Emilia dies, showing a complete disregard for anyone except her, and was even willing to destroy the world because of the condition in their contract.
Around 400 years ago, Puck was a human but was created into an Artificial Spirit by Echidna, though he had apparently left her by the time she moved into the Sanctuary. Seven years before the start of the election, Puck unfroze Emilia and began to act as her friend and mentor, and later on, started to live at Roswaal's mansion where he was reunited with Beatrice.
Artificial Spirit: Puck is a Great Spirit presiding over Fire Mana. While he was contracted with Emilia, he used to have a number of conditions, one of which was that he would only appear from nine in the morning to five in the afternoon, though he could use her Od to manifest himself in an emergency. Like Beatrice, Puck is also an Artificial Spirit, making him have a terrible mana consumption rate. He used to drain mana from Emilia, who didn't have any use for it until she remembered that she could use magic on her own during the trials, while lying that he was absorbing it from the atmosphere. Puck had a vow with Echidna that forbade him from forming a contract with Emilia on his own, however he broke this vow as he was on the verge of death, both as a means to save himself and to protect her from the effects of his battle with Melakuera. This resulted in his memories of the past being sealed.
Empath: Puck is capable of reading the surface thoughts or intentions of individuals he comes in contact to an extent. He can also communicate telepathically through this with anyone has an affinity for Spirits even without Emilia being aware.
Decurseifcation: Puck can detect and remove curse according to Beatrice.
Mana Drain: Puck is capable of draining mana by touch. He is the only one besides Beatrice that knows this skill.
Star Beastification (星獣化 Seijuuka): While normally staying in a small size, Puck's true form is a monstrous, 20 meter, golden eyed cat like beast which is dubbed "the Beast of the End". As he needs an incredible amount of mana to stay in this form, he forcibly drains it from his surroundings, causing them to freeze..
Magic User: Puck is able to use Water, Fire, and Yin magic and is also mentioned to use others.
- Shamak (シャマク): Puck's target becomes unable to sense where they are, however they can still feel the ground and sense what is happening to their body.