Most of the series' running gags revolve around Marika's over-the-top antics of pursuing Raku which is usually prevented by either Chitoge and Seishirō that stems from their harbored feelings towards the young man. Still, Marika is known for her unwavering loyalty and affection towards Raku.
As a child, Marika was often accompanied by a young Raku to play at her room since she can't venture outside due to her frail body. Nonetheless, Marika began to fall in love with her only playmate and worked hard to shape herself as the ideal woman for him, such as by abandoning her native speech pattern, learning the ways of acting more femininely and began to grow long hair to appeal to Raku's childhood interest towards the type of girl he wanted.
Marika has no qualms of being betrothed to Raku and even acted to boast about it to ensure that no one would claim Raku away from her. Despite knowing of Raku's relationship with Chitoge, Marika's determination of becoming Raku's life partner never wavered as she never holds back her advances towards Raku despite her weak condition.
Out of all the five girls romantically attracted to Raku, Marika seems to be the more open, vocal yet aggressive. Marika holds Raku in high-esteem and is overly attracted to him. Due to this, Marika almost pays no attention to her surrounding when it comes to her advances towards Raku. Trivially, Marika is the first out of the five girls to have intentionally kissed Raku - twice on the cheek even - with Chitoge to be the first albeit out of an accident.
However, Marika is not above forcing Raku to give in to her advances. This was greatly demonstrated when the two were alone at a ferris-wheel cabin. Despite Marika taking the opportunity of kissing Raku on the lips, Marika reluctantly held herself back. She is also weak when Raku would make the first move on her. As shown during their "date" in the amusement park, Marika acts timid and fidgety when Raku guided her to the rides and sights, much to the latter's uneasiness. Despite this, Marika would still surprise Raku with her advances such as kissing him on the cheek, then teasing Raku in kissing his lips the next time she does. Furthermore, despite being aware of the fact that her feelings for Raku are one-sided and the type of 'relationship' he shares with Chitoge, Marika continued to pursue over Raku assuming that he only used Chitoge as an excuse to reject her and eventually begged for his answer towards her feelings for him. When Raku finally declared that he cannot date Marika, the latter felt relieved and thanked Raku for everything he had done for her sake but reinstated that she will continue to pursue him as well as refine herself during the years they are to be seperated.
All in all, Raku is one of the few persons Marika had shown a manner of genuine respect and politeness. In contrast to other characters, Marika would usually show a slight hint of ignorance and vulgarity when interacting with them. But like most characters, Marika tends to place Raku in embarassing situations that can lead people to make the wrong idea about him. Nonetheless, Marika is strongly serious of her emotions for Raku when she once stated to have already began saving money by taking a part-time job for their future together. Raku would usually be taken aback by Marika's seriousness from time to time.
Once introduced as Raku's girlfriend, Marika began showing her antagonistic side towards Chitoge. Applying Raku's childhood interest towards girls with long hair, Marika openly declares her dislike towards Chitoge. Furthermore, she doesn't seem to view Chitoge as a threat in regards to their feelings towards Raku.
While seemingly looking down on Chitoge, Marika never failed to view Chitoge as a close friend. As the series' progresses, Marika and Chitoge's insults-lashing slowly becomes teasing. Marika also began to warm-up towards Chitoge as the two bonds more frequently. Still, Marika tends to look down on Chitoge for her shortcomings of being Raku's girlfriend, claiming that she is more suited as Raku's lover due to the skills she honed during her time of shaping herself as Raku's ideal woman.
Marika and Kosaki don't have a special relationship. The two seem to be on good terms with each other - seeing each other as friends. Marika, not knowing of Kosaki's feelings for Raku, views Kosaki more as a friend than a usual acquaintnace which may be due to Kosaki's sweet and gentle demeanour or the fact that she doesn't have long hair than most girls. However, Marika has the tendency of teasing Kosaki or placing her in embarassing situations along with the other characters.
Like with Kosaki, Marika and Seishirō's relationship is considered somewhat neutral at best. Most of the time, Seishirō would reprimand Marika for her advancements towards Raku (or jealousy) and Marika would usually feign ignorance. However, seeing as how the two would still result in hanging out with each other, their relationship seems to grow equitably as the two doesn't mind each other's presence. Still, Marika tends to tease Seishirō, most notably due to her busty figure.
Honda is Marika's personal aide who tends to her master's needs in the absence of her parents. However, Marika seems to think that Honda's loyalty is mostly directed towards her mother and thus their relationship can only be labelled as that of a master and a servant and nothing more. Eventually, after Honda defied Chika's orders and helped Marika escape, Marika now thinks to Honda more as a servant and that of a friend she can open up to, being the first or a few to learn Honda's true name.
Marika and Mikage has a somewhat complicated background. In their junior-high, Marika was once bullied by a group being led by Mikage, until they were trampled solely by Marika as she later conquers their entire school. Afterwards, for unknown reasons, the two befriended one another and forged a special bond.
While somewhat annoyed by Mikage's perverse habits, Marika treasures Mikage and their friendship. This was magnified when the two were delighted to see one another after a long time. Marika is also grateful towards Mikage for being her friend and for fulfilling the role of being a "big sister" to her.
Marika and Yui are childhood friends, alongside, Raku, Chitoge and others. However, Marika sees Yui more of a meddler that interferes with her attempts to woo Raku. Nonetheless, Marika refers to Yui in the same way Raku addresses Yui - an older sister - and is generally greatful to be acquainted with her.
Marika and her mother share a troubled relationship. As a child, Marika only had limited interactions with her mother due to her illness and position as the head of their family. Coupled with her mother's cold and unlikeable personality, the animosity between the two only grew bigger with Chika not providing her daughter much liberty in living the life she wanted as she already has made arrangements for Marika's future being their next head which includes disallowing her in pursuing her love interest - Raku. Due to this Marika never spoke to Raku about her mother and once referred to her as a 'mythical beast'.
Unlike with her mother, Marika shares a close relationship with her father as he was the one mostly present in tending with her daughter's needs, including allowing her to be romantically acquainted with Raku through a promise with the latter's father. In general Marika treasures her father dearly despite him being somewhat overprotective towards her daughter.