The Samurai was one of the Elder bairns fought by Saya Kisaragi.
This Elder Bairn is without doubt the most talkative one seen in the series and even teases Saya and taunts her; it even informs her that he felt the "old her" after being defeated by her. It also played mind games with Saya as such before it dies it tells Saya to ask Tadayoshi about who she really is.
In spite of its large size it closely resembles a human male. It has a human-like face and body. Bearing a large shell on it's back it can summon another six arms from dome-like sockets on its back, which all wield identical large Katana's.
He is very large and powerful being multiple feet higher than the average human being. He has six arms that he uses to wield six giant Katanas during combat. He has decent skill in wielding these blades though he over powers his opponents with the size and amount of blades he uses.
He suddenly appears out of the blue from the canal next to the rice fields that Saya passes over to go to school. He emerges as Saya speaks to a policeman about how the school is closed due to the Nene and Nono missing persons investigations. He impales the policeman with his sword and then duels Saya, easily outmatching her with his many blades that he gradually has emerge from his back as the fight wears on. He mocks Saya through the fight, calling her weak and a shadow of her 'former self', which only serves to confuse the girl. Saya suggests that maybe he had fought her mother in the past, but the Samurai just laughs her off. After he threatens to kill Saya's father and has repeatedly slashed her back open, Saya's eyes change to red and she charges at him as he does the same to her. She stabs him through the centre of his sternum, ignoring his thick armour, allowing him to inflict massive slash wounds to her shoulders, which she naturally shrugs off. The Samurai tells her to find out who she really is, as his last act, before she leaps into the air and slices him in two from head to groin - his visor shattering and revealing his full human face before he splits in two and the two halves crash to the ground in an oddly symmetrical way.