The Father Spider Demon was a member of the Spider Family.
After the Older Sister Spider Demon called for him, the Father Spider Demon landed in front of Kamado Tanjirou and Hashibira Inosuke. He angrily told them to get away from his family, attacking them with a fierce punch. He easily blocked Tanjirou's Water Wheel technique, attempting to counter with another punch, only to be thwarted by Inosuke's twin swords pinning his arms down. He threw the two Demon Hunters off of him, immediately charging and attacking Tanjirou while repeating his earlier demand. Inosuke attempted to attack him from behind, only to be immediately punched. The Spider Demon attempted to continue his assault on the pig-headed Demon Hunter, only to be pinned by a tree that Tanjirou had cut. He quickly recovered from this, using the unexpected object to smash his assailant into the distance.
Later, while Inosuke contemplated his next move, the Father Demon attacked him, breaking the tree he was leaning against. Surprised by his opponent's quick retreat into attack, the paternal Demon blocks the strike, but has his forearm severed when Inosuke uses both of his blades. Briefly examining his stump, the Father Demon then retreated, climbed up a tree, shed his skin, and assumed a new form. He then descended the tree, ready to resume the battle.
Towering over his astounded opponent, the Father Demon punched him with great force, following through almost immediately with another blow, which the Demon Hunter avoided by jumping into the air. Inosuke attempted to sever the paternal Spider Demon's neck with his Rip and Devour technique, only for his blades to shatter upon contact. The Father Demon immediately counterattacked, sending his adversary hurtling into yet another tree, and then picked the Demon Hunter up by the throat. Readying another punch while simultaneously throttling his opponent, the Father Demon once again repeated his earlier demand, only to be stabbed in the throat by his resilient adversary. Unfazed, he tightened his grip on the youth's throat, but had his forearm severed once more, this time by the newly arrived Tomioka Giyuu. Howling in pain, the Father Demon immediately regrew it, charging at the Pillar. His offense and existence were soon erased as the veteran Demon Hunter struck him with his Striking Tide attack, severing his neck and cutting him to pieces.