Samson is Filia's Parasite, whose being essentially replaces her hair and augments her overall strength. The two share a symbiotic relationship, and are shown to be on generally good terms with each other with Samson being both protective and supportive of Filia. Filia seems to have met Samson's acquaintance relatively recently, with her receiving amnesia upon becoming Samson's host. Reasons to how and why Samson got attached to Filia are kept vague, with the only known information being that it originates from an unknown event that occurred in her mysterious past. In her current state, Filia seems very reliant on Samson in their day-to-day life and seems to wholly trust him – likely a product of having no one else to turn to in hopes of regaining her memory and the knowledge of the ongoing threat of the Skullgirl. Likewise her loss of memories have left her with a very naïve personality, a trait that is implied to have been different before becoming a host to Samson.
Despite the twosomes close relationship and necessity to live off one another, their companionship can be strenuous at times, almost exclusively at Filia’s expense. Samson’s general brash and rowdy personality in addition to his bluffing and gambling bother Filia frequently, with her having no power over his actions and her protests generally succumbing to no avail. Similarly she is subject to the side-effects of his parasitism, where the consequences of elements such as eating, drinking and pain are symbiotic between the two of them (the former solely effecting Filia as the host of the relationship). It is also implied that Samson could be hiding important facts from Filia as hinted on several occasions, such as being hesitant on the subject of Painwheel knowing Filia after their fight during Story Mode. Likewise, Parasoul’s defeat quote against Filia "You're… being used." and Leviathan’s Story Mode quote "I won't idly watch you bring doom to another host!" suggests that Samson's intentions towards Filia might be less honorable then on the outset and gives the notion that he has manipulated his previous hosts prior to attain his goals.
Despite this, Samson has also shown genuine compassion for Filia and seems to have her best interests in mind – offering the option to stop the pursuit of finding the Skullheart if she so wishes during Squigly’s Story Mode (in spite of him seemingly pushing Filia towards it beforehand) and also attempting to defend Filia’s life at the end of Eliza’s Story Mode, even though Eliza’s intention is to replace Filia with a better vessel for him. In Filia’s unused alternate Story Mode ending, Samson also makes the implication that Filia had asked him to erase her memories in the first place. Samson furthermore provides shelter for Filia, persisting many of his contacts and “friends” to get him and Filia a place to sleep for the night, due to her not having a home of her own. In public he also typically remains hidden from sight due to knowing the predigest parasites and their users receive (though it could be argued the latter two details would benefit Samson himself just as much as it would Filia).