|This article is about a/an villain and a Dark Knight in Garo: Honoo no Kokuin|
Dario was a blind Makai Knight who had been missing for some time until he suddenly reappearing during the events of Garo: Divine Flame. In the past, Dario was the personal bodyguard of Sara, the princess of the Vazelia Kingdom, and held a high degree of loyalty and affection towards her. He is also the inheritor of the title and armor of Zem the Obsidian Knight (黒曜騎士ゼム Kokuyō Kishi Zemu).
Dario was one of the royal guards protecting the Kingdom of Vazelia, who was fond of Princess Sara. During one of the training exercises, he single-handily beat all of the other guards. Princess Sara, who was watching the battle, went down and complimented him and said that everyone considered him to be Vazelia's strongest knight. One day while walking with Sara, Dario tries to convince her to stop walking on the ledge of the bridge, but she happily assures him that it is going to be okay since he is there to protect her. One night, when a Horror invaded the castle, Dario as Zem saved the princess from being eaten. But it was too late, the Horror's poisonous saliva burned her face, this made her fall into despair and eventually she burned the kingdom. Dario, not wanting to leave her side, blinds himself out of guilt so she would not feel shame about her appearance. After everything burned, Princess Sara tells Dario goodbye and jumps off the bridge, where she is pulled by Nigra Venus. Nigra then goes up and pulls Dario down to the lake, where he drowns.
Dario first appeared saving Leon from Nigra Venus' servants and introduces himself, Zaruba begins to suspect Dario, but he manages to convince Leon. Dario then tells Leon that he knows where the servants took Roberto and proceeds to take him there, on the way however, they encounter a newly resurrected Germán Luis who explains his current situation. The three of them reach the temple, but are attacked by a Madō Tool. Dario then disappears amidst the battle to overlook German and Leon fight the tool. After German and Leon destroy the Madō Tool, they save "Roberto", but they are shocked that it was a decoy. The last thing German sees is Dario, who quickly transformed before the bomb goes off. After Garm protects German and Leon, they chase Dario in their steeds. Leon and Dario fight, until Leon manages to knock Dario off his steed, the two of them demand answers and Dario tells his story. German and Luis eventually get to Vazelia and save Ema, Leon then fights Nigra Venus until she attacks him from behind. Dario then appears behind Leon and reveals to him that he has become a dark knight, Dario then impales Leon and sees his most tragic memories. Seeing how Leon couldn't protect the person he loved just like him, Dario offers Leon to join him. But German saves Leon, and escape. Once Leon and German return, the three of them fight in their steeds over the lake.Alfonso then takes German's place so that he could save Roberto, but when German is about to save Roberto, Dario appears and stops him. Dario then breaks the chain holding Roberto in place, and its capsule begins to fall, but German dives in to catch the capsule. Leon quickly catches German's dagger, but Dario steps on him to make him release the chain. Just when he is about to make Leon release the chain, Dario turns his attention on Alfonso, who is about to kill Nigra Venus. Dario promising Nigra that he is not going to fail her again, throws her into Zirkel's Ring. Nigra Venus now restored pulls Dario into the Gate too, seemingly ending all this. But Jiruba cracks open and the Zirkel's Ring reappears, revealing Sir Venus, the merged state of Nigra Venus and Dario.
Zem, The Obsidian Knight
As a Makai Knight, Dario is given the title of The Obsidian Knight. As such, he has the ability to don the Zem Armor. He does this by pointing his spear up in the air and drawing a large circle above him. The circle opens the portal, where the armor descends and equips on him, completing the transformation.
Dario first appeared in this form, saving Leon from Nigra Venus' servants.
- Makai Spear - Since this spear has a bladed cross on one end and the spearhead on the other, Zem can either use the bladed cross to slice horrors or use the spear part to impale his enemies. Zem can also throw the spear at great ranges to take down its target.
After revealing himself as one of Nigra Venus' servants, he quickly changes into his corrupted form. In this form, Zem retracts his mask making a wolf-like face and gains purple accents all around his armor. After impaling a target, Zem can engulf them in Purple Madō fire that allows him to see the impaled target's most tragic memories.