Klug

Klug is a male member of Primp Town, debuting in Puyo Puyo Fever. He is known to be stuck up and rude. He is commonly perceived as a geek or nerd, or "goody two shoes". He has brown hair and is clad in purple. The book he is always seen carrying is actually from the library, and he continues to keep it through renewal. His birthday is on September 29th. He is called "Glasses" by his friend Sig due to the fact that they are classmates and friends.

Because of his envy for Lemres, Klug is often also depicted by fans as being in love with Lemres. Official content however has not gone any further than suggesting deep obsession or envy.

In Puyo Puyo Fever 2, Klug was possessed by his own book and became Strange Klug aka Possessed Klug who has the same birthday as Sig.

amitie
Klug is classmates with Amitie as seen in the first Fever! games. Despite her kindness, Klug does not hold back from poking fun at her ditzy personality or her lack of skill with magic.
feli
Klug's admiration for Lemres naturally makes him a target for Feli. Feli hates Klug for trying to be like Lemres and trying to get close to Lemres, seeing his actions as a threat to her attempts to get into a relationship with Lemres. Klug is often depicted as being terrified of Feli due to her constant threats and attitude towards him.
lemres
Klug admires Lemres deeply, wanting to be as powerful as him one day. The two get along well unlike Sig who dislikes him. Lemres supports Klug's magic studies and plays Puyo Puyo matches with him so that he has a chance to demonstrate his newfound knowledge. Although nothing regarding the topic has been explicitly stated in official media, many have inferred that Klug may have a crush on Lemres.
lidelle
While Lidelle and Klug's relationship isn't expanded upon greatly, it seems that they are at least on somewhat friendly terms. As he entrusts her to deliver a letter inviting Amitie to the Arca Ruins in Puyo Puyo Fever 2. Lidelle also cared enough about Klug's desire for Amitie to come meet him to challenge her to a Puyo battle immediately after.

She is also the one who persuaded him to come back home in Puyo Puyo Chronicle, granted this was less because of her concerns and more because he didn't want to lose his status as an honors students.
maguro sasaki
Klug was used as a test subject for Maguro's beauty beams in Puyo Puyo!! 20th Anniversary. He was also investigating the magic of Maguro's kendama in Amitie and the Girl of Love.
ms. Accord
Ms. Accord is Klug's teacher at Magic School. She seems to appreciate his ambition, but says that Klug's mischievousness and schemes are inconvenient and concerning
raffina
Klug absolutely despises Raffina, as he tends to clash with her due to them both having prideful personalities.

raffina
While they could be viewed as friends, Raffina thinks of him as an annoying and stuck up bookworm.